8
Apr,1999CPM-300
4.2. DSP
When the test is successful, the program turns off the
LED and proceeds to the test 5. If the test fails, the pro-
gram lights the LED 4 times and won’t proceed to the
test 5.
To force the test program to proceed to the test 5, press
and hold AUTO SET until the test continues.
5. Level balance
Connect the audio generator to any of channels 1 to 6 and set
the audio generator to the value shown below.
Waveform :Sine
Output level :as appropriate
Input Level :+4dB
Frequency :1 kHz
Set the CPM-300 as follows (controls on a channel are for the
channel carrying the test signal):
Channel controls
SENS : +4 dBm (full-counterclockwise)
HIGH : Center
LOW : Center
SEND : Center
PAN : Center
FADER:At "0" on the scale
Master controls
SEND : 0 (full-clockwise)
FADER : At "0" on the scale
Connect oscilloscope input to MIXER OUT: L and R
This is to keep a level balance between DSP board output
and THRU output.
While repeatedly pressing ANTI FEEDBACK ON/OFF switch,
turn TIME knob which should vary the channel L output wave-
forms on the scope gradually. Adjust TIME knob until the
waveform on the scope is maintained almost at the same
upon ON and OFF of ANTI FEEDBACK switch. During this
adjustment, AUTO SET LED blinks at a slower rate.
Repeat the procedure for the R channel but this time adjust
LEVEL knob.
Press AUTO SET to save the settings into memory. The pro-
gram proceeds to the test 6.
6. Anti-feedback
Connect the audio generator to any of channels 1 to 6 and set
the audio generator to the value shown below.
Waveform : Sine
Output level : As specified in a step
Frequency : As specified in a step
Set the CPM-300 as follows (controls on a channel are for the
channel carrying the test signal):
Channel controls
SENS : +4 dBm (full-counterclockwise)
HIGH : Center
LOW : Center
SEND : Full-counterclockwise
PAN : Center
FADER : At "0" on the scale
Master controls
SEND : Full-counterclockwise
FADER : At "0" on the scale
Connect oscilloscope input to: MIXER OUT L and R
Apply the following steps to the L channel and repeat for the
R channel.
6.1 Set the audio generator to the values shown below.
Output level : +4 dBm
Frequency : 100 Hz
Press ANTI FEEDBACK switch to ON and verify smooth
fading of the output.
6.2 Set the audio generator to the values shown below.
Output level : +4 dBm
Frequency : 1 kHz
Press ANTI FEEDBACK switch to ON and verify smooth
fading of the output.
6.3 Set the audio generator to the values shown below.
Output level : +4 dBm
Frequency : 10 kHz
Press ANTI FEEDBACK switch to ON and verify smooth
fading of the output.
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