-SQA-SCOTTISH QUALIFICATIONS AUTHORITY HIGHER NATIONAL UNIT SPECIFICATION GENERAL INFORMATION

Transcription

1 -SQA-SCOTTISH QUALIFICATIONS AUTHORITY HIGHER NATIONAL UNIT SPECIFICATION GENERAL INFORMATION -Unit Number Superclass- -Title- XM RADIO COMMUNICATION CIRCUITS DESCRIPTION- GENERAL COMPETENCE FOR UNIT: Analysing the operation of circuits found in radio communication equipment. OUTCOMES 1. analyse the operation of radio frequency amplifiers for a range of system bandwidths; 2. analyse the operation of interstage coupling and matching circuits; 3. analyse the operation of oscillator and frequency synthesis circuits; 4. describe the circuit operation of a radio receiver; 5. analyse the circuit operation of radio transmitters. CREDIT VALUE: 2 HN Credits ACCESS STATEMENT: Access to this unit is at the discretion of the centre. However, it would be beneficial if the candidate had prior knowledge of analogue electronics. This may be evidenced by possession of HN Unit: Analogue Electronics: Semiconductor Parameters and Applications Telecommunication Fundamentals Single Phase AC Networks or similar qualifications or experience

2 For further information contact: Committee and Administration Unit, SQA, Hanover House, 24 Douglas Street, Glasgow G2 7NQ. Additional copies of this unit may be purchased from SQA (Sales and Despatch section). At the time of publication, the cost is 1.50 (minimum order 5.00). 2

3 HIGHER NATIONAL UNIT SPECIFICATION STATEMENT OF STANDARDS UNIT NUMBER: UNIT TITLE: RADIO COMMUNICATION CIRCUITS Acceptable performance in this unit will be the satisfactory achievement of the standards set out in this part of the specification. All sections of the statement of standards are mandatory and cannot be altered without reference to SQA. OUTCOME 1. ANALYSE THE OPERATION OF RADIO FREQUENCY AMPLIFIERS FOR A RANGE OF SYSTEM BANDWIDTHS PERFORMANCE CRITERIA (a) (b) (c) (d) (e) Analysis of the operation of tuned class A amplifiers is accurately completed. Explanation of the use of cascode connected amplifiers in radio frequency stages of transceivers is clear and complete. Explanation of the use of narrow, intermediate and wideband amplifier circuitry is clear and complete. Identification of the main sources of internal noise is clear and correct. Calculation of Noise Figure for a given RF amplifier configuration is correct. RANGE STATEMENT Internal noise: thermal; short; partition. EVIDENCE REQUIREMENTS Written and graphical evidence of a report, is required to show the candidate can competently analyse the operation of a given radio frequency systems as detailed in performance criteria (a) - (e). Calculations, written and graphical evidence of the candidate s ability to meet performance criterion (d) - (e). 3

4 OUTCOME 2. ANALYSE THE OPERATION OF INTERSTAGE COUPLING AND MATCHING CIRCUITS PERFORMANCE CRITERIA (a) (b) (c) (d) Analysis of the performance of a directly coupled amplifier is accurate and complete. Analysis of the performance of choke, capacitance coupled amplifier is accurate and complete, over a range of frequencies extending beyond cut-off. Analysis of the methods and performance of a tuned transformer coupled amplifier is accurate and complete over a range of frequencies covering the bandwidth. The explanation of use of a common collector amplifier as a matching device is clear and accurate. RANGE STATEMENT Transformer coupled: single tuned; double tuned. EVIDENCE REQUIREMENTS Written and graphical evidence to show that the candidate has correctly analysed the performance of each method of coupling as required by the performance criteria (a) to (c). Written evidence to show that the candidate understands the use of a common collector amplifier as detailed in performance criterion (d). OUTCOME 3. ANALYSE THE OPERATION OF OSCILLATOR AND FREQUENCY SYNTHESIS CIRCUITS PERFORMANCE CRITERIA (a) (b) (c) (d) (e) (f) Explanation of the operation of fixed frequency and variable frequency oscillator circuits is correct. Calculation of oscillator circuit parameters is correct in terms of resonant frequency and loop gain necessary for oscillation. Analysis of a variable frequency oscillator is clear and complete. Explanation of factors affecting stability of oscillator operation is complete and correct. Description of the operation of a frequency multiplier circuit is correct. Description of the operation of a given digital frequency synthesis system is clear and correct 4

5 RANGE STATEMENT Fixed and variable oscillators: crystal; colpitts; Hartley. Stability: amplitude at various frequencies ; amplitude and frequency for a +/- 10% change in nominal supply voltage Digital frequences syntheses: Phase Locked Loop (PLL); frequency divider; reference frequency; frequency pre-scaling. EVIDENCE REQUIREMENTS Graphical and written evidence to show that the candidate can, in respect of oscillatory circuits, explain circuit actions, perform parameter calculations and explain the factors affecting stability as stated in performance criteria (a) to (d). Written and graphical evidence that the candidate can describe the operation of frequency multiplier circuit as specified in performance criterion (e). OUTCOME 4. DESCRIBE THE CIRCUIT OPERATION OF A RADIO RECEIVER PERFORMANCE CRITERIA (a) (b) (c) Description of the function and operation of each stage in a radio receiver is correct. Explanation of the terms, image channel and adjacent channel, is clear and correct. Explanation of the factors governing choice of intermediate frequency and local oscillator frequency is complete and correct. RANGE STATEMENT Radio receiver: Superheterodyne; input protection; RF amplifier; mixer; local oscillator; IF amplifier; AGC; demodulator; AF amplifier. Choice of intermediate frequency and local oscillator frequency: RF bandwidth; IF bandwidth; image channel interference; adjacent channel interference. EVIDENCE REQUIREMENTS Written evidence showing the candidate s knowledge and understanding of the function of radio receiver circuits as detailed in the performance criteria (a) to (c) and covering the full range statement. 5

6 OUTCOME 5. ANALYSE THE CIRCUIT OPERATION OF RADIO TRANSMITTERS PERFORMANCE CRITERIA (a) (b) (c) (d) (e) Description of the operation of circuits associated with transmitter signal level control are correct. Description of the operation of transmitter control circuits are correct. Interpretation of the action of radio transmitter circuits are correct. Analysis of the operation of transmitter final stage amplification is correct. Analysis of radio frequency transmitter final stage matching networks is correct. RANGE STATEMENT Signal level control: audio signal automatic level control; RF drive signal level control. Control circuits: keying of high level circuits; keying of low level circuits; shaping of switched waveform. Transmitter circuits: exciter; buffer; drive amplifier; modulation amplifier; final amplifier. Transmitter final stage amplification: efficiency; bias considerations; drive level. Matching networks: T ; pi. EVIDENCE REQUIREMENTS Written evidence showing the candidate s knowledge and understanding of the circuit function of a transmitter as detailed in the performance criteria (a) to (e) and covering the full range statement. MERIT To gain a pass in this unit, a candidate must meet the standards set out in the outcomes, performance criteria, range statements and evidence requirements. To achieve a merit in this unit, a candidate must demonstrate a superior or more sophisticated level of performance. This may be demonstrated by: (i) (ii) (iii) analytical skills; logical presentation of work; expressing and presenting answers to descriptive questions

7 ASSESSMENT In order to achieve this unit, candidates are required to present sufficient evidence that they have met all the performance criteria for each outcome within the range specified. Details of these requirements are given for each outcome. The assessment instruments used should follow the general guidance offered by the SQA assessment model and an integrative approach to assessment is encouraged. (See references at the end of support notes). Accurate records should be made of the assessment instruments used showing how evidence is generated for each outcome and giving marking schemes and/or checklists, etc. Records of candidates achievements should be kept. These records will be available for external verification. SPECIAL NEEDS Proposals to modify outcomes, range statements or agreed assessment arrangements should be discussed in the first place with the external verifier. Copyright SQA 1997 Please note that this publication may be reproduced in whole or in part for educational purposes provided that: (i) (ii) no profit is derived from the reproduction; if reproduced in part, the source is acknowledged. 7

8 HIGHER NATIONAL UNIT SPECIFICATION SUPPORT NOTES UNIT NUMBER: UNIT TITLE: RADIO COMMUNICATION CIRCUITS SUPPORT NOTES: This part of the unit specification is offered as guidance. None of the sections of the support notes is mandatory. NOTIONAL DESIGN LENGTH: SQA allocates a notional design length to a unit on the basis of time estimated for achievement of the stated standards by a candidate whose starting point is as described in the access statement. The notional design length for this unit is 80 hours. The use of notional design length for programme design and timetabling is advisory only. PURPOSE This unit is to prepare candidates for further radio circuit development in telecommunications or radio frequency engineering. CONTENT/CONTEXT The following information gives further clarification regarding the context in which the outcomes and performance criteria are to be achieved. The unit is designed to develop competence in the appraisal of electronic circuits found in communication equipment. The unit is designed as an integrated block of learning outcomes such that on achievement of all performance criteria the operation and behavioural response of a complete communications system should be realised. The theoretical knowledge requirement for this unit would be best assessed by structured questions and assignments and practical exercises if appropriate. Amplifiers: MF; HF; VHF; using valve; transistor; integrated circuits. APPROACHES TO GENERATING EVIDENCE This unit should be carried out in a situation where candidates have access to a range of live transceiver installations. Practical demonstration of circuit behaviour/operation should be encouraged as a lead-in to investigative studies. ASSESSMENT PROCEDURES Centres may use the Instruments of Assessment which are considered by tutors/trainers to be the most appropriate. Examples of Instruments of Assessment which could be used: 8

9 Outcome 1 Structured questions using supplied circuit diagrams and a report on a laboratory test. A report on the test of a tuned amplifier to contain details of equipment used, procedure of the test, drawing of circuit under test, tabulated results, graph of gain in db and phase against log of frequency. Outcome 2 Structured questions, assignment or case study and a report on a laboratory test. Written report for performance criteria (a) to (c) should contain full details of equipment used, procedure of the test, drawing of circuit under test, tabulated results, graphs of attenuation in db and phase against log of frequency. Outcome 3 Structured questions using supplied circuit diagrams and a report on a laboratory test. Graphical and written report for performance criterion (c) should contain full details of equipment used, procedure of the test, drawing of the oscillator under test, tabulated and graphical display of results and recommendations for ensuring stability of amplitude and frequency of an oscillator subjected to supply voltage variations. Outcome 4 Structured questions and assignment or case study using supplied radio receiver diagrams. Outcome 5 Structured questions and assignment or case study using supplied transmitter diagrams. PROGRESSION HND second year Telecommunications Engineering or Radio Frequency Engineering or Marine Electronic Engineering. REFERENCES 1. Guide to unit writing. 2. For a fuller discussion on assessment issues, please refer to SQA s Guide to Assessment. 3. Information for centres on SQA s operating procedures is contained in SQA s Guide to Procedures. 4. For details of other SQA publications, please consult SQA s publications list. 9

10 Copyright SQA 1997 Please note that this publication may be reproduced in whole or in part for educational purposes provided that: (i) (ii) no profit is derived from the reproduction; if reproduced in part, the source is acknowledged. 10