2 GS/s High-Speed Digitizers: Optimized for Automated Test

Transcription

1 2 GS/s High-Speed Digitizers: Optimized for Automated Test NI PXI-5153, NI PCI-5153, NI PXI-5154, NI PCI GS/s maximum real-time sample rate 300 MHz, 500 MHz, and 1 GHz bandwidths Up to 20 GS/s equivalent-time sampling 2 channels simultaneously sampled Edge, window, hysteresis, digital, immediate, and software triggering Overview The NI PXI-5153, PCI-5153, NI PXI-5154 and PCI-5154 are four of the NI high-speed digitizers/pc-based oscilloscopes that provide the industry s first gigahertz solutions optimized for automated test. A digitizer optimized for automated test takes advantage of a high-throughput bus to lower test times, offers picosecond-level synchronization between modules, and integrates with the entire suite of NI hardware including arbitrary waveform generators, high-speed digital I/O, and other digitizers so you can build and customize a complete mixed-signal or high-channel-count test system. Application and Technology NI High-Speed Digitizers: Optimized for Automated Test Prior to these products, high-bandwidth digitizers and oscilloscopes incorporated features and functionality best suited for benchtop use. An unaddressed area in this high-bandwidth space has been the automated test use model, where measurement throughput and test system footprint can dramatically affect overall cost of test. NI high-speed digitizers are the first high-bandwidth digitizers on the market to share three characteristics that make them uniquely optimized for automated test: high data throughput, tight synchronization between channels, and ease of integration with other instruments. provides high speed due to the high-bandwidth and low-latency PCI and PCI Express buses. Both PXI and PXI Express data throughput rates are significantly faster than that of GPIB, USB, or LAN other popular buses for automating test instrumentation. This translates to lower test times. Figure 1. The PXI platform provides the best combination of high-bandwidth and low-latency measurement throughput. Tight Synchronization between Channels The PXI backplane offers a built-in common reference clock for synchronization of multiple digitizers in a measurement or control system. Each slot has a 10 MHz TTL clock, transmitted on equallength traces, providing picosecond-level synchronization between digitizer modules for high-channel-count systems. For example, it is possible to have 34 phase-synchronous 1 GS/s channels in a single PXI chassis, and scale to even higher-channel counts. High Data Throughput Bus bandwidth and latency, two common considerations for an automated test system, dictate the overall speed of your measurement system. Latency describes the amount of time it takes for an instrument to respond to a remote command, like a measurement query. Bus bandwidth refers primarily to the data throughput capacity of the data bus that connects the measurement instrument with the host PC or controller. The PXI platform upon which NI high-speed digitizers are built Figure 2. The PXI platform delivers picosecond-level synchronization. 25

2 2 GS/s High-Speed Digitizers: Optimized for Automated Test Ease of Integration with Other Instruments Test systems typically contain many instrument types, including signal sources, measurement devices, and switches. The PXI platform has unparalleled breadth, with modules for analog and digital I/O, high-speed instrumentation, vision, motion, and numerous bus interfaces. More than 1,500 PXI modules are available from the more than 70 members of the PXI Systems Alliance (PXISA). So you can not only build a comprehensive Figure 3. The PXI platform supports more than 1,500 instrument modules. 26

3 150 MS/s, 16-Bit Digitizer for Communications NI PXIe MS/s real-time sample rate 3 to 250 MHz band in direct path mode, or 50 MHz bandwidth centered at MHz 16-bit resolution Ability to stream to disk at maximum sample rate for hours with PXI Express Quadrature digital downconversion (DDC) with up to 60 MHz IF bandwidth AC coupled only Alias-protected decimation for all sample rates Overview The NI PXIe-5622 is a 150 MS/s digitizer with onboard signal processing (OSP). OSP functions include quadrature digital downconversion (DDC), real digital downconversion, and antialias filtering. The NI PXIe-5622 is ideal for communications applications with its high dynamic range front end and a high-throughput PXI Express interface, allowing it to stream IF data to disk for hours at the full 150 MS/s sample rate. 27

4 400 MS/s, 16-Bit, Dual-Channel Arbitrary Waveform Generator NI PXIe-5451 Time domain, I/Q, and IF signal generation 16-bit resolution, 400 MS/s sampling rate per channel 145 MHz analog bandwidth, ±0.34 db flatness to 120 MHz with digital flatness correction 98 db close-in SFDR at 1 MHz -146 dbc/hz phase noise density at 10 khz offset -160 dbm/hz average noise density 25 ps channel-to-channel skew Continuous data streaming >600 MB/s from host Overview The NI PXIe-5451 is a 16-bit, 400 MS/s, dual-channel arbitrary waveform generator. It features both single-ended and differential outputs with two analog paths for maximum flexibility and performance. Each of the outputs features up to 98 db of spuriousfree dynamic range (SFDR) at 1 MHz (without harmonics), better than -146 dbc/hz phase noise density at 10 MHz (10 khz offset), and less than 25 ps channel-to-channel skew. The NI PXIe-5451 is the ideal instrument to test devices with I/Q inputs, generate multiple wideband signals, or serve as the baseband component of an RF vector signal generator. It also features onboard signal processing (OSP) functions that include digital upconversion, pulse shaping and interpolation filters, gain and offset control, and a numerically controlled oscillator (NCO) for frequency shifting. Common applications include prototyping, validating, and testing of semiconductor components and communications, radar, and electronic warfare systems. With its NI Synchronization and Memory Core (SMC) architecture, the NI PXIe-5451 helps you integrate mixed-signal test systems by enabling synchronization with other instruments such as vector signal analyzers/generators, high-speed digitizers, digital waveform analyzers/generators, and other signal generators. You can also synchronize multiple arbitrary waveform generators to form a phase-coherent multichannel generator for applications such as MIMO (multiple-input, multiple-output) or beamforming antenna schemes. Application and Technology Signal Quality and Flexibility With 16 bits of resolution, the NI PXIe-5451 achieves a close-in SFDR (without harmonics) of 98 db at 1 MHz on the performanceoptimized direct path. Including harmonics and measured from DC to 200 MHz, it achieves a 10 MHz SFDR of 75 db and a wideband SFDR of 72 db at 60 MHz. IMD at 10 MHz is -84 dbc, and the noise floor is also extremely low at -160 dbm/hz. These specifications provide the dynamic range and out-of-band performance needed to meet the stringent demands of baseband I/Q signal generation (Figure 1). Figure 1. With its high sample rate and resolution, the NI PXIe-5451 generates low-distortion, high-sfdr signals over a very high bandwidth (the noise floor is limited by the measurement device). The main path, while optimized for flexibility, achieves similar levels of performance. It features a variable analog gain stage with 63 db of range and four digits of adjust, capable of generating signals using the full 16-bit resolution of the main digital-to-analog converter (DAC) from 5 Vpk-pk (differential, into 100 Ω) down to 1.77 mvpk-pk (single-ended, into 50 Ω). A novel architecture provides DC offset independent of gain, allowing small AC signals on top of high-bias voltages, which are useful for stimulating single-supply components. Other benefits of the main path include a softwareenabled reconstruction filter and software-selectable single-ended and differential outputs. 28

5 400 MS/s, 16-Bit, Dual-Channel Arbitrary Waveform Generator The NI PXIe-5451 also delivers exceptional passband flatness (Figure 2). While the -3 db analog bandwidth of the direct path is 145 MHz, the digital flatness correction filter provides ±0.34 db of flatness from DC to 120 MHz. On the main path, the flatness correction filter provides ±0.50 db of flatness from DC to 120 MHz. Figure 2. Passband flatness (direct path) is significantly improved with the use of digital flatness correction in the NI PXIe-5451 FPGA. For maximum signal purity, the phase noise of this module is extremely low. The phase noise density of a tone generated at 10 MHz drops from -121 dbc/hz at a 100 Hz offset to -152 dbc/hz at 100 khz, yielding an integrated system output jitter of less than 350 fs. Its highly stable phase-locked loop (PLL) and high-resolution oscillator provide an output sample rate resolution less than 5.7 μhz, enabling low phase noise signal generation at any frequency with microhertz resolution. High-Speed Data Streaming In addition to tight synchronization, the SMC architecture on the NI PXIe-5451 takes advantage of the PCI Express bus to continuously stream data from the host controller at more than 600 MB/s in dual-channel mode or at 360 MB/s when generating on a single channel. This enables the module to continuously output I/Q waveforms at 150 MS/s, or, when upconverted, approximately 120 MHz RF bandwidth, either from host memory or a high-speed storage solution such as the NI HDD TB RAID array. With this technology, you can generate terabyte waveforms of unique, high-bandwidth data for several hours. Applications that benefit from this capability include RF and baseband recording and playback for signals intelligence and communications system design, validation, and verification. Onboard Signal Processing OSP significantly extends waveform playback time and shortens waveform download times (Figure 4). A field-programmable gate array (FPGA) on the NI PXIe-5451 implements the OSP functionality, which enables several signal processing and I/Q-related functions. An essential attribute for I/Q generation is tight synchronization between channels. The NI PXIe-5451 features high-performance circuitry that calibrates the channel skew to within 25 ps. You can achieve even more alignment with a 10 ps resolution programmable skew, which is useful in calibrating out cable length mismatches. This tight level of synchronization minimizes the phase error between channels, especially at high frequencies, which is essential for accurately generating high-bandwidth I/Q signals (Figure 3). Figure 4. OSP on the NI PXIe-5451 FPGA performs inline processing of waveform data before it is sent to the digital-to-analog converter (DAC). Digital upconversion (DUC) Converts complex waveform data to a real signal centered at an intermediate frequency and generated out of a single analog channel. The DUC supports I/Q rates up to 200 MS/s and bandwidths limited by the analog bandwidth of the NI PXIe-5451, or 0.8 times the I/Q rate, whichever is lower. Complex frequency shifting Shifts complex waveform data higher or lower in frequency and generates separate analog I and Q signals. Independent I and Q prefilter gain and offset Adds gain and offset imbalance impairments and I and Q prefilter gain. You can adjust the offset before or during the generation of an output signal (figures 5, 6). Figure 3. Dedicated channel-alignment circuitry automatically calibrates the two channels on the NI PXIe-5451 to within 25 ps. This particular module exhibits less than 13 ps of skew, demonstrated on a 100 MHz sinusoid. 29

6 400 MS/s, 16-Bit, Dual-Channel Arbitrary Waveform Generator Baseband interpolation Generates smooth baseband signals with integer interpolation. You can use the NI PXIe-5451 OSP block to interpolate low-sample-rate waveforms to a much higher sample rate, thereby improving the output frequency spectrum by relocating zero-order sample-and-hold reconstruction images to higher frequencies. With the images at higher frequencies, the device s image-suppression filter greatly suppresses them without disturbing the signal s amplitude response or phase information. Figure 5. LO leakage and poor image rejection of a quadrature modulator cause undesired RF emissions. Figure 6. On-the-fly-adjustable parameters on the NI PXIe-5451 correct for the quadrature modulator impairments seen in Figure 5. Waveform Sequencing and Triggering You also can program the NI PXIe-5451 to sequence and loop a set of waveforms. You can choose from several methods to step through the sequence of waveforms. In cases when you know the duration of each waveform in advance, you can program the generator to loop them a specified number of times. When you do not know the duration before the start of generation, you can use a hardware or software trigger to advance the generator to the next waveform in the sequence. The NI PXIe-5451 implements advanced triggering behavior with four trigger modes: single, continuous, burst, and stepped. In addition, scripting provides the ability to link and loop multiple waveforms together, managing triggers and markers. For a detailed discussion of these modes, consult the NI Signal Generators Help guide available at ni.com/manuals. NI SMC-based generators have the unique capability of storing multiple sequences and their associated waveforms in the generator s onboard memory (see Figure 7). In automated test applications involving multiple tests, each requiring a different waveform sequence, you can download all of the sequences and waveforms once at the beginning of the test cycle and store them in the generator s memory for the entire session. By downloading all required waveforms and sequences once to an SMC-based generator instead of repeatedly reloading them for each test, you save time and improve throughput. Pulse-shaping finite impulse response (FIR) filter Shapes and interpolates the waveform data. FIR filter types include flat, raised cosine, and root raised cosine, with a programmable a parameter. Digital interpolation factors range from 2 to 32,768 times. Numerically controlled oscillator (NCO) Produces sinusoidal waveform data for complex (I/Q) frequency shifts before or during generation with up to a ±86 MHz shift and 710 nhz resolution. NCO tuning time is 250 μs. Figure 7. NI SMC-based arbitrary waveform generators increase test throughput by storing all the waveforms and sequences required for a set of tests in onboard memory. Timing and Synchronization Using NI T-Clock (TClk) synchronization technology, you can synchronize multiple NI PXIe-5451 modules for applications requiring a greater number of channels, such as I/Q signal generation for MIMO systems. Because it is built into the SMC, TClk can synchronize the NI PXIe-5451 with SMC-based vector signal analyzers and generators, high-speed digitizers, and digital waveform generators and analyzers for tight correlation of analog 30

7 400 MS/s, 16-Bit, Dual-Channel Arbitrary Waveform Generator and digital stimulus and response. Using onboard calibration measurements and compensation, TClk can automatically synchronize any combination of SMC-based modules with less than 500 ps module-to-module skew. Greatly improved from traditional synchronization methods, the skew between modules does not increase as the number of modules increases. To achieve even better performance, you can use a high-bandwidth oscilloscope to precisely measure the module-to-module skew. With the oscilloscope measurement for calibration information, TClk can achieve <20 ps module-to-module skew. NI PXIe-5451 clocking is flexible. Its internal, DDS-based clock is optimized for phase noise performance, and has better than 5.7 μhz frequency resolution. The module can also import its sample clock from the CLK IN front panel connector and multiply and divide this clock s frequency by integers. Finally, the NI PXIe-5451 can phase-lock its internal clock to an external reference or the PXI 10 MHz reference clock. 31

8 16-Channel, 50 MS/s, 14-Bit Digitizer Adapter Module for NI FlexRIO NI simultaneously sampled 50 MS/s channels 14-bit vertical resolution 2 Vpp, 50 Ω single-ended inputs with DC coupling 8 general-purpose digital input and output lines for system stimulus and control Well-suited for applications ranging from research to large-scale deployment Requires NI FlexRIO FPGA module Overview Experiments and measurements in areas such as experimental physics, nondestructive test, and medical imaging can span across tens or hundreds of channels, requiring not only a system with high-channel density but also a way to retrieve and transfer the data and/or measurements of interest. The NI 5751 digitizer adapter module for NI FlexRIO provides the unique combination of highchannel density, scalability with PXI and PXI Express, and a fully programmable FPGA, which you can add for tasks such as custom triggering or inline signal processing. Eight digital inputs and outputs offer further benefits as system stimulus or control signals. Application and Technology Key Specifications Specification Sample Rate Resolution Number of Channels Bandwidth Input Range Coupling Input Impedance Crosstalk Table 1. Key Typical Specifications of the NI 5751 Analog Input 50 SM/s 14 bits 16, single-ended 26 MHz 2 V DC 50 Ω -75 db (1 HMz) -65 db (5 MHz) Figure 1. NI 5751 Characteristic Dynamic Performance, Spectrum 64 k Samples, 5.3 MHz, -1 dbfs Input Signal Application Areas Application High channel-count advanced diagnosis Complex detector systems Tomography High-resolution time domain measurements Table 2. Applications and Example Algorithms for the NI 5751 Example Algorithms Data reduction, custom and event-based triggering Combinational logic for advanced triggering on transient events Data reduction, FFT, cross-correlation Custom data triggers, hysteresis, time in region, timing and voltage measurements Combined with an NI FlexRIO FPGA module, the NI 5751 provides a powerful solution for applications requiring a high-channel-count digitizer with low crosstalk, the small form factor and scalability of PXI, and a user-accessible FPGA for custom real-time processing. 32

9 Baseband Transceiver for NI FlexRIO NI 5781R Dual 100 MS/s, 14-bit inputs Dual 100 MS/s, 16-bit outputs 2 Vpp differential I/O (1 Vpp single-ended capable) 40 MHz bandwidth (-3 db) External clock input and output 8 general-purpose digital I/O lines Overview The NI 5781 is an analog dual-input, dual-output NI FlexRIO adapter module optimized for interfacing with baseband to RF upconverters and downconverters. When you pair it with an NI FlexRIO fieldprogrammable gate array (FPGA) module, the resulting NI 5781R is an FPGA-enabled RIO baseband transceiver that you can use to implement custom RF modulation and demodulation, channel emulation, bit error rate testing, or spectral monitoring and jamming. Additionally, you can use the low latency and high throughput of FPGA-based processing for ultrahigh-speed control and inline processing applications. Application and Technology Key Specifications The NI 5781 features dual, simultaneously sampled, 14-bit, 100 MS/s differential inputs and dual, simultaneously generated, 16-bit, 100 MS/s differential outputs. Connectivity includes MCX connectors for the eight differential analog input and output lines, clock input, and clock output, along with a 9-pin DIN connector for auxiliary digital I/O. You also can use the module in single-ended mode with the supplied 50 Ω terminators. Table 1 shows the key specifications. Specification Analog Input Analog Output Sample Rate 100 MS/s 100 MS/s Resolution 14 bits 16 bits Number of Channels 2 2 Bandwidth (-3 db) 40 MHz 40 MHz Range (differential) 2 Vpp 2 Vpp Range (single-ended) 1 Vpp 1 Vpp Coupling DC DC Impedance 50 Ω 50 Ω SFDR (@ 5 MHz) 70 dbc 64 dbc THD (@ 5 MHz) -70 dbc -64 dbc Average Noise Density (DC to 50 MHz) -136 dbm/hz -146 dbm/hz Phase Noise Density (@ 10 MHz, 1 khz offset) -127 dbc/hz -127 dbc/hz Table 1. Key NI 5781 Specifications The analog input on the NI 5781 provides the high dynamic range and low noise necessary for acquiring and demodulating baseband communication signals. Figure 1 shows these attributes through the acquisition of a 5 MHz tone. Figure 1. A 5 MHz Tone Acquired by the NI 5781 The analog outputs offer equally high dynamic characteristics (Figure 2) and feature onboard interpolation to sample rates up to 400 MS/s for attenuating the high-frequency reconstruction images found on all digital-to-analog converters (DACs). Figure 2. A 5 MHz Tone Generated by the NI

10 Baseband Transceiver for NI FlexRIO Application Areas The NI 5781 is optimized for interfacing with baseband to RF upconverters and downconverters. In these applications, the two inputs or outputs of the NI 5781 acquire or generate the in-phase and quadrature (I and Q) or real and imaginary components of the downconverted or upconverted RF signals. With 40 MHz of baseband bandwidth on each of the I and Q channels, you can access up to 80 MHz of RF bandwidth. filtering to remove out-of-band noise. These operations are often performed in real time and can return data to a host processor for additional calculation and logging, or you can regenerate the processed signal for interfacing with other equipment. On the NI FlexRIO FPGA, RF signals can be measured, generated, modulated, demodulated, filtered, decoded, and more. In radio applications, on the FPGA you can implement various layers of a communications standard most often the modulation, demodulation, and tuning, but other layers including coding are also possible. For RF signal test and signals intelligence (SIGINT) applications, you can convert the time domain I and Q signals into the frequency domain and compare the resulting frequency spectrum with an arbitrary mask to implement a real-time spectrum analyzer. You can use this technology to identify unanticipated transmitters in signals intelligence or to ensure proper spectral performance of the device under test (DUT) in test applications. Also, you can add custom filtering, delay, and nonlinearities to acquired signals for immediate generation in custom channel emulation applications, where the low latency and high throughput of an FPGA are critical. Beyond RF, the NI 5781 is useful in frequency-based control. In these applications, high-frequency sinusoids are the stimulus and response signals, so you need a high-bandwidth front end for acquisition and generation. While the NI 5781 samples and generates at 100 MS/s, or with a period of 10 ns, pipelining on the analog-to-digital converter (ADC), DAC, and FPGA, along with the algorithm running on the FPGA, introduce latency. Without any processing, the latency of the NI 5781 is shown in Table 2. DAC Interpolation DAC Interpolation Disabled Enabled Input-to-Output Latency 350 ns 550 ns Table 2. Input-to-Output Latency of the NI 5781 Depending on the complexity of the algorithm on the FPGA, additional latency can range from tens of nanoseconds to several microseconds. Architecturally similar to control applications, inline processing with the NI 5781 helps you add FPGA-defined functionality to your baseband signals. Possible algorithms include delay generation for precision phase control, notch filtering to eliminate unwanted tones coupling into a signal, custom triggering for data reduction, or noise 34

11 300 Mbit/s, 32 SE and 16 LVDS Digital Adapter Module for FlexRIO NI (32 Data + 3 PFI), and 2 Clock Single Ended Channels Selectable voltages from 1.2 to 3.3V with 10 bit resolution (High levels only) 19 (16 Data + 3 PFI), and 2 Clock differential signals (-01 part number for LVDS and -02 part number for mlvds) Max 200 MHz clock rate (Up to 300 Mbps in double data rate mode) Simultaneous operation of all single ended and differential channels at up to 300 Mbits/s (mlvds to 200Mbits/s) Mates with NI-FlexRIO FPGA module for programmable FPGA and IP integration capabilities Overview The NI 6583 is a mixed logic 200 MHz digital adapter module for NI FlexRIO field-programmable gate array (FPGA) modules. This adapter module features single ended and differential signaling (LVDS or mlvds) channels capable of up to 200 MHz clock rates with up to 300 Mbps data rates using double data rates (DDR) on a 150 MHz sample clock (sampling on the both the rising and falling edges of the clock). Single Ended The 32 single ended channels feature selectable voltages between 1.2 and 3.3V with a 10 bit resolution. These are individually controlled hardware timed bidirectional channels and are thus ideal for protocol communication with as SPI and I2C. Differential The 16 differential channels are also individually controlled hardware timed bidirectional channels capable of up to 300 Mbps data rates. Note: The -01 part number offers low voltage differential signals (LVDS) and the -02 part number offers multipoint LVDS (mlvds) signals. You can use the LabVIEW FPGA programmable onboard FPGA to emulate custom or standard digital protocols, perform onboard analysis such as real time hardware compare or even embed existing VHDL IP. 35

12 Battery Simulator Optimized for Mobile Device Test NI PXIe-4154 Overview The NI PXIe-4154 battery simulator is a specialized programmable power supply optimized for mobile device test. It features a 6 V, 3 A programmable output designed to simulate a lithium-ion battery cell s transient speed, output resistance, and 2-quadrant operation (source/sink). Critical to many RF and wireless applications, the simulator s ultrafast transient response time - software-selectable to <20 µs or <40 µs - allows it to rapidly respond to changes in load current with minimal voltage dip. This makes it ideal for powering devices under test (DUTs) such as RF power amplifiers, cellular handsets, and a variety of other mobile devices. To model the behavior of a battery even more accurately, you can use the onboard programmable output resistance of up to 1 Ω to simulate a battery s internal resistance. For quiescent and standby current measurements, the NI PXIe-4154 features integrated current measurement with down to 1 µa sensitivity. It also offers a supplemental 8 V, 1.5 A charger simulator channel for testing power management ICs along with the battery simulator channel. Both channels on the NI PXIe-4154 feature integrated voltage and current readback with up to 200 ks/s continuous acquisition rates, ideal for characterizing transient behavior. You also can sequence and trigger outputs and measurements via the PXI backplane for synchronization with digital I/O and RF instrumentation. Requirements and Compatibility OS Information Windows 7 Windows Vista Windows XP Driver Information NI-DCPower Software Compatibility LabVIEW LabWindows/CVI NI TestStand Development System Visual Basic.NET Visual C++ Visual Studio.NET Comparison Tables Output voltage, current Transient response time Max sample rate (voltage and current) Sense capability Programmable output resistance Hardware sequencing/triggering NI PXIe-4154 Battery Simulator +6 V, ±3 A (battery simulator channel) <20 µs, <40 µs - software-selectable NI PXI-4130 Power SMU ±20 V, ±2 A (SMU channel) NI PXI-4110 DC Power Supply +6 V, 1 A; +20 V, 1 A; -20 V, 1 A <200 µs (typical) <150 µs (typical) 200 ks/s 3 ks/s 3 ks/s Remote (4-wire), local - software selectable -40 mω to 1 Ω, programmable in 1 mω steps Remote (4-wire), local - software selectable Local (2-wire) sense only PXI backplane Application and Technology Transient Response and Voltage Dip When testing mobile devices, it is essential that the power source recovers quickly; otherwise, the performance of the device under test (DUT) is affected adversely during testing. Large, instantaneous changes to the load current drawn by the DUT result in an output voltage dip as the control circuitry of a power supply acts to restore the output voltage to its original value. On typical programmable 36

13 Battery Simulator Optimized for Mobile Device Test power supplies, this can often take hundreds of microseconds. Conversely, the 20 µs transient response of the NI PXIe-4154 (available when set to fast mode) allows the simulator to quickly respond to changes in load current during tests. This short recovery time is optimal for many wireless communications devices that implement pulsed communications protocols. drop as higher currents are drawn. As the current increases, the internal voltage drops due to Ohm s Law (V=I R). This causes the voltage at a battery s terminals to decrease as the current increases. If the internal resistance and the current drawn from a battery are high enough, the output voltage can drop significantly, regardless of how much charge it is holding. For battery-operated devices, if the voltage drops below a certain threshold, it causes the device to shut down. This demonstrates the large role internal resistance can play when testing battery-operated products. Figure 1. Transient Response and Voltage Dip Most mobile devices today incorporate low-battery-detection circuitry. Conventional power supplies often exhibit a large voltage dip, as seen in Figure 1. When the power output drops below the detection circuitry s low-power threshold as the result of voltage dip, the mobile device shuts down, causing a false indication of a failed device. To eliminate these false failures during test, the NI PXIe-4154 has a specified transient response dip of less than 70 mv (when set to fast mode). Figure 2. LabVIEW Example Code for an RF Power Amplifier (PA) Showing Transient Response and Voltage Dip Adjustable Internal Resistance As nonideal voltage sources, batteries have internal series resistance. This internal resistance varies based on the chemistry used for different battery types. The internal resistance can be affected by variables including how the battery is used, level of charge, and age. Internal resistance causes a battery s voltage to You can program channel 0 of the NI PXIe-4154 to vary the output resistance from -40 mω to 1 Ω in 1 mω increments. The positive range of the output resistance allows the channel to emulate the internal resistance of a battery over its lifetime. The negative resistance range allows you to compensate for voltage drops due to resistive losses between the remote sense points and the DUT terminals. Accurate Leakage Measurements and High-Speed Waveform Capture The integrated measurement circuits on each channel of the NI PXIe-4154 can simultaneously read the voltage and current at the output terminals (local sense) or sense terminals (remote sense). These measurements are performed on each channel by two 16-bit analog-to-digital converters one for the voltage, and one for the current which are synchronized at all times. Both converters run at a rate of 200 ks/s, allowing for continuous, high-speed waveform captures of voltage and current, which you can use to characterize the transient characteristics of a mobile device s power consumption. For improved noise performance, you can use the NI PXIe-4154 to automatically average multiple samples to increase the effective resolution of measurements. On the included ±30 ma current range, the NI PXIe-4154 offers down to 1 µa measurement sensitivity, so you can characterize standby and leakage currents on mobile devices and RFICs. Charger Simulator The NI PXIe-4154 battery simulator channel is capable of sinking high currents in quadrant II, so you can simulate a rechargeable battery. The charger simulator channel is a complementary power supply channel capable of sourcing 1.5 A at 8 V. With this additional channel, you can characterize the behavior of a mobile device when recharging a battery. Connect the charger simulator channel of the NI PXIe-4154 to the charger port on a mobile device and monitor current draw as the device operates in battery charge mode. 37

14 Analog/Digital Audio Generator and Analyzer NI AudioMASTER for Analog and Digital Audio Comprehensive set of audio measurements using single and multiple tones, amplitude and frequency sweeps, and step response analysis Advanced limit testing capabilities using window, tunnel, or point limits Analog audio generation and analysis at up to ks/s with 24 bits of resolution Digital audio analysis and generation for S/PDIF interfaces with sample rates from 22 to 192 khz Point-and-click application development with NI AudioMASTER software Overview NI AudioMASTER is a set of versatile audio test solutions for analog and digital audio validation and production test. It melds modular hardware components with application-specific software to create a powerful and easy-to-use audio test platform. NI AudioMASTER for Analog Audio combines a high-performance NI 4461 dynamic signal acquisition (DSA) device, featuring 24-bit resolution, a ks/s sample rate, two inputs, and two outputs, or an NI 4462 DSA device, featuring 24-bit resolution, a ks/s sample rate, and four inputs, with NI AudioMASTER software for the acquisition, analysis, and generation (NI 4461 only) of analog audio. simplifies the development of automated audio tests and measurements by providing an interactive, configuration-based setup for audio measurements, limit evaluation, and system calibration. NI AudioMASTER also offers a LabVIEW API (DigAudio) for digital audio measurements that you can use with the NI Sound and Vibration Measurement Suite for customized analog and digital audio measurements. With tightly synchronized I/O, NI AudioMASTER is an ideal solution for mixed-signal audio tests that integrate both analog and digital requirements. NI AudioMASTER for Digital Audio combines an NI 7813R reconfigurable I/O device and either the NI CB-2180 (2-input) or CB-2181 (1-output, 1-input) digital audio accessory with the same NI AudioMASTER software for generating, acquiring, and analyzing S/PDIF or AES3 audio with LPCM or AC3 encoding over coaxial, optical, or XLR connections. NI AudioMASTER for HDMI Audio is an add-on feature to the NI VideoMASTER Digital Video (HDMI/DVI) Analyzer. It combines the NI PXI-2172 HDMI deserializer and decryption module and an NI 7813R reconfigurable I/O device with the same NI AudioMASTER software for analyzing HDCP-encrypted HDMI audio with up to 24-bit resolutions and 192 khz sampling rates. Application and Technology NI AudioMASTER offers easy-to-use GUIs with a comprehensive set of audio measurements using single tone, multitone, amplitude sweep, frequency sweep, and step response analysis optimized for automated test. It features custom test steps that are directly integrated into NI TestStand test management software, which Figure 1. With NI AudioMASTER, you can perform a comprehensive set of audio measurements and system calibration using the interactive step types for NI TestStand. NI AudioMASTER for Analog Audio NI AudioMASTER for Analog Audio includes the following components: NI PXI-4461 or PCI-4461 DSA device with 24-bit resolution, ks/s sample rate, two inputs, and two outputs or NI PXI-4462 or PCI-4462 DSA device with 24-bit resolution, ks/s sample rate, and four inputs NI AudioMASTER software DVD Required license for analog audio measurements 38

15 Analog/Digital Audio Generator and Analyzer Analog Audio Performance The analog input channels of NI 446x devices have 24-bit resolution analog-to-digital converters (ADCs) that are simultaneously sampled at software-programmable rates at up to ks/s. The analog inputs offer a programmable gain amplifier stage with gain selections from -20 to +30 db in 10 db steps that accept differential or single-ended signal connections. The input channels also provide software-selectable AC/DC coupling and Integrated Electronic Piezoelectric (IEPE) conditioning of 0, 4, or 10 ma for IEPE microphones. NI 446x device inputs deliver high dynamic range of 118 db, amplitude flatness of ±0.006 db (20 Hz to 20 khz), and low distortion of -107 db of THD+N (20 Hz to 20 khz). NI 4461 devices also feature two analog output channels with 24-bit resolution digital-to-analog converters (DACs) that are simultaneously updated at software-programmable rates at up to ks/s. The analog outputs offer a programmable attenuation of 0, 20, or 40 db (±10, 1, or 0.1 Vpk) with differential or pseudodifferential output configurations. A common application of the analog output is to stimulate a device under test while measuring the response with the analog inputs. You can simultaneously acquire data on the input channels while updating the output channels. The inputs and outputs of an NI 4461 are also sampled coherently, making NI 4461 devices ideal for stimulusresponse audio tests. NI 4461 outputs deliver high dynamic range of 113 db, amplitude flatness of ±0.008 db (20 Hz to 20 khz), and low distortion of -97 db of THD+N (20 Hz to 20 khz). Acoustical and Electroacoustical Tests In combination with NI 446x devices, you can use NI AudioMASTER software in NI TestStand to perform acoustical and electroacoustical tests in a wide range of applications including loudspeakers, headsets, microphones, media players, and televisions. Designed for coherent and noncoherent test environments, NI AudioMASTER can be used to set up coherent tests where the signal generation (output to the device under test, or DUT) is synchronized with the signal acquisition (output from the DUT), and the frequencies and timing functions are related in an exact integer ratio. For noncoherent test setups, NI AudioMASTER can apply various windowing functions to minimize the challenges that arise in noncoherent test environments. Typical noncoherent cases include the output testing of a CD, DVD, MP3, or media player, where the audio output is independent (free-running) with respect to the acquisition instrumentation. Included with NI AudioMASTER, the calibration manager helps you calibrate against system-level nonlinearities that occur when using anechoic test chambers, artificial mouths, microphones, and other test system interfaces. Calibration Tool and Manager Several acoustical test components such as anechoic test chambers and rooms are inherently nonlinear. In addition, acoustical features can change as a result of different environmental parameters such as the surrounding air pressure. NI AudioMASTER offers an advanced, easy-to-use tool suite to calibrate acoustical characteristics. You can use the calibration tool to calibrate anechoic test chambers, anechoic rooms, artificial mouths, microphone test stands, and other test system interfaces and devices. You can implement the calibration procedure after you define the input and output calibration parameters in a calibration window. With the calibration manager, you can enforce specific calibration intervals. If expired, a calibration action can automatically be initiated, or the user can be prompted to take the appropriate action. NI AudioMASTER for Digital Audio NI AudioMASTER for Digital Audio includes the following components: NI PXI-7813R or PCI-7813R R Series reconfigurable I/O device NI AudioMASTER software DVD Required license for digital audio measurements CB-2180 (2-input) or CB-2181 (1-output, 1-input) digital audio accessory (add-on) Digital Audio Testing Using the PXI-7813R or PCI-7813R R Series device and a CB-218x digital audio accessory with NI AudioMASTER software in NI TestStand, you can perform digital audio test S/PDIF audio including Linear PCM and AC-3 (5.1 Surround Sound) over coaxial, optical, or XLR interfaces. Common devices include set-top boxes, DVD players, amplifiers, loud speakers, and home theater systems. You can configure digital audio signals such as sweeps and tones in the NI AudioMASTER software, or you can specify a digital file containing the audio stream to generate. The CB-2180 provides two input channels, each with a softwareselectable BNC for coaxial or TOSLINK for optical connection. You can connect up to four CB-2180 digital audio accessories to a single NI 7813R device to provide a total of eight S/PDIF inputs. The CB-2181 offers one input channel and one output channel, each with a software-selectable BNC for coaxial, TOSLINK for optical, or XLR for AES3 connection. You can connect up to four S/PDIF outputs and four S/PDIF inputs. With the multiple input and output channels in each NI 7813R device, NI AudioMASTER greatly simplifies the test fixture required for multidevice testing. 39

16 Analog/Digital Audio Generator and Analyzer test engineers can develop and perform optimized measurements and tests on a wide variety of audio products including set-top boxes, media players, headphones, microphones, and loudspeakers. It improves user productivity in test application development as well as test execution time in validation and production testing. The result is shorter development times for test applications and optimized test times for automated tests. Figure 2. The NI CB-2180 (top) and NI CB-2181 (bottom) Digital Audio Accessories HDMI Audio Testing NI AudioMASTER for HDMI Audio is an add-on solution to the NI VideoMASTER Digital Video (HDMI/DVI) Analyzer. It uses the PXI-2172 deserializer and decryption module (from the NI VideoMASTER Digital Video (HDMI/DVI) Analyzer) to remove any HDCP encryption and transmits the HDMI audio to an NI 7813R reconfigurable I/O device where it is acquired and analyzed. NI AudioMASTER for HDMI Audio supports audio in SPDIF and I2S formats at 16 to 24 bits per sample per channel. SPDIF can support two channels of L-PCM encoded audio or encoded bitstreams such as AC3 up to six channels (5.1 channels). I2S can support up to eight channels of L-PCM encoded audio or high-definition encoded formats. Customized Audio Measurements You also can combine NI AudioMASTER with NI sound and vibration software to develop your own customized audio measurements. Using NI AudioMASTER, you can quickly set up your test system to generate the required stimulus signal to the DUT and/or acquire the response using the interactive configuration-based interface in NI TestStand. The software can then apply your system calibration parameters to the acquired waveform before passing it to your custom audio measurements written in LabVIEW or other application development environments using local variables in NI TestStand. NI sound and vibration software includes numerous algorithms and functions for audio measurements and is shipped with several examples so you can quickly build customized audio measurements to use with NI AudioMASTER. Fast Automated Test Development You can develop test programs quickly with a configuration-based programming approach, for which you control the hardware and software by setting a few parameters using the NI AudioMASTER step type interfaces for NI TestStand. When you have configured your tests and various measurements using interactive step types in NI TestStand, you can run the program to obtain the test results, compare these results to defined limits, generate a report, and store the measurement results to a database. You can also view live measurement results, including frequency response and distortion curves, during development and debugging by pressing an execute button in the NI AudioMASTER step type interfaces. For limit testing, the software incorporates graph limits to enable vectorbased limits using window limits, tunnel limits, or point limits that can be static or floating. NI AudioMASTER has several built-in checks that protect against incorrect measurement setups and inconsistent measurement results. NI AudioMASTER is a highly efficient solution that combines hardware and software so that users from novice to experienced 40