Assignment - Audio connectivity and interface techniques
Tasks
Background information
This assignment allows learners to demonstrate their knowledge and practical ability in connecting together analogue and digital systems. Learners will demonstrate basic fault finding skills on an analogue system.
Task A -
i - Produce a block diagram and notes
Learners are required to measure and note down the signal levels throughout a recording system by using a test tone at the input that produces an output level of "0 Vu" (PPM 5) at the output sockets feeding the multi-track recorder.
The signal chain should cover the signal source through to the multi-track input and the multi-track output back to monitoring section.
Use of the patch bay and access to in/out connectors should be used to measure these levels throughout the signal chain. Each point in the system should be assessed as to whether it is balanced or unbalanced.
Learners should present this information as a block diagram.
Learners should make notes showing how these points may be used in the process of fault finding either by injecting a test signal or by signal monitoring and measurement.
Ii - Locate a fault
Learners are required to determine the position of a fault in a signal chain using the techniques indicated in task Ai above. Learners should use logical and efficient processes to locate the fault.
Task B - Implement interfacing, produce a diagram and notes
Learners are required to carry out the interfacing of both:
- an unbalanced consumer level input of a device from a balanced professional level desk output
- an unbalanced consumer level output of a device to a balanced professional level desk input.
Learners should produce a tested interface and submit the following:
- a signal flow diagram
- notes of calculations
- an explanation of the earthing use
- an explanation of the differences between professional and consumer systems
- a brief test report.
Task C -
i - Produce a report
Learners are required to produce a report explaining the fundamental processes and operation of the following digital audio signal chain with master word-clock:
20 bit analogue to digital converter comprising anti-alias filter (AAF), dither generator, sample and hold and quantiser
AES interface with manual selection of channel status
20 bit digital to analogue converter including reconstruction filter
master word-clock.
ii - Implement and construct a cable
Learners are required to implement and construct a cable to convert between an AES digital output to SPDIF digital input.
Learners should demonstrate the correct operation of the interface and produce notes describing the operation of the interface. They should also produce any relevant calculations and describe limitations in the use of channel status information that is transferred.