DVO902 E/S CATV FIBRE TRANSMITTER

Transcription

1 Timo Rantanen (5) DVO902 E/S CATV FIBRE TRANSMITTER DVO902 E and S types are high performance, extremely linear DFB laser transmitters for DVO fibre optic CATV link. DVO902 is available on different optical output power categories to fit different performance requirements. The output power range is from +2 m up to +15 m. DVO902 is fully compatible with DVX Head End system and the module can be installed into a standard DVX installation frame. Features Standardised input and test point levels Broadcast and narrowcast inputs with adjustments High narrowcast isolation Integrated pre and driver amplifiers Automatic power control as a standard feature Built in pilot generator Local and remote software control of all adjustments Management features Monitoring of APC (Automatic Power Control) functionality with user configurable offset Optical output power monitoring Laser bias current monitoring TEC (Thermo-Electric Cooler) current monitoring Laser temperature monitoring Broadcast input equaliser adjustment Narrowcast input signal back off adjustment Signal level adjustment LED indicators for signal and module statuses Internal temperature measurement and monitoring Uptime and total uptime counters Local PC connection through backplane DVO bus with DVX021 cable Remote IP connection through DMM / DSM / DBM controller module

2 Timo Rantanen (5) Technical specifications Parameter Specification Note Optical parameters Light source Cooled DFB with optical isolator Peak wavelength 1310 nm 1) Output power, nominal value 2) Category m Category m Category m Category m Category m Category m Category m Category m Category m Category m Relative intensity noise -155 c/hz 3) 1 ch CENELEC 42 chs 4) Number of optical outputs 1 RF parameters Frequency range MHz RF impedance 75 Ω Input return loss 18 5) Flatness ±0.4 6) Automatic power control (APC) Yes 7) Laser test point level for 4.5 % OMI 78 µv 8) Pilot frequency 43.4, MHz 9) Pilot level 0 / ) Broadcast input Input level 77 µv 11) Level adjustment range 10 Equaliser adjustment range 0 6 Narrowcast input Narrowcast loading 20 pcs. 256-QAM signals Input level Broadcast input level ) Level adjustment range 30 13) Narrowcast isolation 60 14) Noise and distortion performance CENELEC, 42 unmodulated channels Enhanced Standard Link C/N with 0 m to receiver ) and 15) CTB, guaranteed value ) CSO, guaranteed value ) NTSC 77, unmodulated channels Enhanced Standard Typical link C/N with 0 m to receiver ) and 15) CTB, typical value ) CSO, typical value ) CENELEC 42 ch is analog loading up to 862 MHz. NTSC 77 is analog loading up to 550 MHz. Digital channels can be placed everywhere in the frequency spectrum in both cases taking into account the additional loading they create.

3 Timo Rantanen (5) Notes General Power consumption 18 W 18) Supply voltages 24 V / 570 ma 12.5 V / 130 ma 6.3 V / 400 ma RF connectors IEC female Optical connector SC/APC, FC/APC, E ) Dimensions 6U x 7HP x 170 mm Weight 1.5 kg EMC compatibility EN ) Operating temperature range C Storage temperature range C Operating relative humidity 0 85% 1) Typical peak wavelength at 25 C. The peak wavelength variation range between various transmitters is ±20 nm. 2) The inaccuracy of the output power is -0.5/+0.9 compared to the nominal value except on the categories 1, 2, 3 and 4 the inaccuracy is -0.5/+1.9. The category of the transmitter depends on the output power and the maximum (distortion limited) optical modulation index (OMI). The C/N values are based on the fibre length up to 10 km and the noise current density of 7 pa/ Hz. See graphs below. Longer fibres may have an impact on C/N depending on the input power of the receiver, the optical modulation index, the properties of the fibre and also the chirp characteristics of the laser. For instance the fibre of 25 km causes typically penalty on C/N when 0 m is delivered to the receiver. C/N 56,0 54,0 52,0 Noise current density 7 pa/sqrt(hz) Channel Bandwidth 4,75 MHz Responsivity 0,85 A/W RIN -155 c/hz C/N () SMF 10 km 50,0 Output power OMI 4,5 % 48,0 +15 m +14 m +13 m 46,0 +12 m +11 m 44,0 +10 m +8 m +6 m 42,0 +4 m +2 m 40, Optical attenuation () 3) Maximum value. 4) Typical value. The minimum value is 4.0 %. With NTSC 77 typical OMI value is 4.0 %. 5) Typical value is >18 on the whole frequency band. The minimum value is 18 and above 40 MHz -1 / octave. 6) Typical value. Maximum value is ±0.75. Note that the narrowcast branch does not contain an equalizer and the narrowcast branch negative slope can be up to 1. 7) APC is based on broadband detection in which the total laser driving power is measured and adjusted so that if the RF power is evenly divided into 42 channels the resulted OMI/channel is 4.5 %. Off-set can be set by the user. 8) Typical accuracy is ±0.4. Maximum value is ± ) The frequency is set by a user.

4 Timo Rantanen (5) 10) The pilot level compared to the carrier levels. The pilot level has been adjusted to 4.5 % OMI at the factory. 11) Input level required to reach 4.5 % OMI with adjustments in 0 positions. 12) With the narrowcast attenuator set to 0 position, the narrowcast input level has to be 10 higher than the broadcast input level to reach the same OMI in laser. (no back-off) 13) An additional 30 adjustment range compared to broadcast adjustments. The narrowcast signal back-off is adjusted with this. 14) Narrowcast isolation means the wanted-to-unwanted narrowcast signal level difference at the transmitter output. The unwanted signal leaks from one transmitter to another through the broadcast signal splitter. 15) Typical value with 10 km fibre. The minimum value is 53 with 4.5 % OMI. With NTSC 77 the CNR values are achieved with 4.0 % OMI. 16) Minimum value at 25 C with CENELEC 42 channel raster. Standard performance transmitter has 1 lower distortion specification between 750 and 862 MHz, meaning 64 and 59. With modulated channels the distortion distances are better, CTB typically 8, CSO 6. 17) With modulated channels the distortion distances are better, CTB typically 8, CSO 6. 18) At 25 C. The thermoelectric cooler of a laser is supplied by +6 VDC line. 19) The connector type is specified by a customer. 20) Radiation limit 20 pw. Block diagram Broadband Detector Laser TP Narrowcast Input Main Input E O Optical Output

5 Timo Rantanen (5) Ordering information Product name Description DVO902/1 E Output power +2 m and enhanced performance DVO902/2 E Output power +4 m and enhanced performance DVO902/3 E Output power +6 m and enhanced performance DVO902/4 E Output power +8 m and enhanced performance DVO902/5 E Output power +10 m and enhanced performance DVO902/6 E Output power +11 m and enhanced performance DVO902/7 E Output power +12 m and enhanced performance DVO902/8 E Output power +13 m and enhanced performance DVO902/9 E Output power +14 m and enhanced performance DVO902/10 E Output power +15 m and enhanced performance DVO902/1 S Output power +2 m and standard performance DVO902/2 S Output power +4 m and standard performance DVO902/3 S Output power +6 m and standard performance DVO902/4 S Output power +8 m and standard performance DVO902/5 S Output power +10 m and standard performance DVO902/6 S Output power +11 m and standard performance DVO902/7 S Output power +12 m and standard performance DVO902/8 S Output power +13 m and standard performance DVO902/9 S Output power +14 m and standard performance DVO902/10 S Output power +15 m and standard performance