Optimod-AM 9400 V1.2 Operating Manual - Orban

3-54
OPERATION ORBAN MODEL 9400
back and forth randomly if the stereo content is right at the stereo /
mono detector’s threshold. Mono music with a “speech-like” envelope
may be incorrectly detected as “speech.” Music incorrectly detected as
“speech” will exhibit a slight loss of loudness and punch, but misdetection
will never cause objectionable distortion on music.
Speech that is not located in the center of the stereo sound field will always
be detected as “music” because the detector always identifies stereo
material as “music.” This can increase clipping distortion on such
speech.
Because the speech detector uses information about the stereo sound
field to help make its detection more accurate, it is important to feed the
9400 with stereo source material even if it is only being used to drive a
monophonic AM analog transmitter.
If the BASS CLIP MODE is set to HARD, the speech/music detector will automatically
set it to MEDIUM when speech is detected and HARD otherwise
(unless LATENCY is LOW, in which case MEDIUM bass clipping is unavailable
and bass clipping will stay HARD).
Speech always sounds cleaner with MEDIUM bass clipping and the increased
bass “punch” supplied by HARD is irrelevant to speech.
This control does not affect the digital radio processing chain.
Test Modes
Setup: Test
Parameter
Units Default Range (CCW to CW) Step
Labels
MODE --- Operate Operate, Bypass, Sine, Square, ---
Triangle
BYPASS GAIN dB 0.0 18 … +25 1
SINE FREQ Hz 400 16, 20, 25, 31.5, 40, 50,
LOG
63, 80, 100, 125, 160,
200, 250, 315, 400, 500,
630, 800, 1000, 1250, 1600, 2000,
2500, 3150, 4000, 5000,
6300, 8000, 9500, 10000, 12500,
13586.76, 15000
SQUARE FREQ Hz 400 16, 20, 25, 31.5, 40, 50,
LOG
63, 80, 100, 125, 160,
200, 250, 315, 400, 500,
630, 800, 1000
TRI FREQ Hz 100 Fixed at 100 Hz
SINE/TRINGL MOD % 100 0 … 121 1
SQUARE MOD % 30 0 … 50 1
TONE CHAN --- L+R L+R, LR, LEFT; RIGHT ---
Table 3-10: Test Modes
The Test Modes screen allows you to switch between OPERATE, BYPASS, and SINE,
SQUARE, or TRIANGLE. When you switch to BYPASS or any tone mode (sine wave,