Field Audit Of Performance - Orban OPTIMOD 6300 Operating Manual

4-6
MAINTENANCE

Field Audit of Performance

Required Equipment:

Ultra-low distortion sine-wave oscillator / THD analyzer / audio voltmeter
With verified residual distortion below 0.01%. 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.

Digital voltmeter
Accurate to ±0.1%.

Oscilloscope
DC-coupled, triggered sweep, with 5M Hz 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 6300'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. If it is doing so, there is a high probability that the DSP is
performing the dynamic signal processing correctly. There is therefore no need to
measure such things as attack and release times—these are defined by software and
will automatically be correct if the DSP is otherwise operating normally.
It is often more convenient to make measurements on the bench away from high RF
fields which could affect results. For example, in a high RF field it is very difficult to
accurately measure the very low THD produced by a properly operating 6300 at
most frequencies. However, in an emergency it is usually possible to detect many of
the more severe faults that could develop in the 6300 circuitry even in high-RF envi-
ronments.
See the assembly drawings in Section 6 for component locations. Be sure to turn the
power off before removing or installing circuit boards.
Follow these instructions in order without skipping steps.
Note: To obtain an unbalanced output, connect pin 1 (ground) to pin 3, and meas-
ure between pin 1 (ground) and pin 2 (hot).
ORBAN MODEL 6300