Field Audit Of Performance - Orban Optimod-FM 8300 Operating Manual

4-6
MAINTENANCE

Field Audit of Performance

c) Reconnect the three-wire cable at the back of the encoder.
14. Replacing the Top Cover:
A) Place top on unit and reattach the eighteen Phillips screws. (Be careful not to
pinch any cables.)
Required Equipment:

Ultra-low distortion sine-wave oscillator / THD analyzer / audio voltmeter
With verified residual distortion below 0.01%. Sound Technology 1710B;
Audio Precision System One, or similar high-performance system.
The NAB Broadcast and Audio System Test CD is an excellent source of
test signals when used with a high-quality CD player.

Spectrum analyzer with tracking generator
Stanford Research Systems SR760 or equivalent. Alternatively, a sweep
generator with 50-15,000 Hz logarithmic sweep can be used with an os-
cilloscope in X/Y mode, or you can use a computer-controlled test set like
the Audio Precision System One.

Digital voltmeter
Accurate to ±0.1%.

Oscilloscope
DC-coupled, triggered sweep, with 5 MHz or greater vertical bandwidth.

Two 620 ±5% resistors.

Optional: Audio Precision System 1 (without digital option) or System 2 (for digi-
tal tests).
It is assumed that the technician is thoroughly familiar with the operation of this
equipment.
This procedure is useful for detecting and diagnosing problems with the 8300's per-
formance. It includes checks of frequency response, noise and distortion perform-
ance, and output level capability.
This performance audit assesses the performance of the analog-to-digital and digi-
tal-to-analog converters and verifies that the digital signal processing section (DSP)
is passing signal correctly. Ordinarily, there is a high probability that the DSP is per-
forming the dynamic signal processing correctly. There is therefore no need to meas-
ure such things as attack and release times — these are defined by software and will
automatically be correct if the DSP is otherwise operating normally.
ORBAN MODEL 8300