Tait T830 Series, Руководство по обслуживанию

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Copyright TEL 31/01/96
2.7 Audio Processor
Figure 2.3 T835 Audio Processor Block Diagram
The recovered audio on pin 7 of IC303 is processed in a third order elliptic active filter to
give the required response. Linking (PL101 & PL103) is available to give either a flat or
de-emphasised audio response, with de-emphasis giving a 6dB/octave roll off. The out-
put of IC101 is split to provide separate paths for the speaker and line outputs.
The speaker volume is set using the front panel volume knob (RV103) and the line level
is set using the recessed potentiometer (RV102). The signals are passed to audio drive
amplifiers IC102 and IC103. Under muted conditions the inputs of these amplifiers are
shunted to ground via transistors Q105 and Q106 respectively.
The audio output of IC102 has a DC component which is removed by C122, and this
then drives a speaker directly. The output of IC103 is fed into a line transformer to pro-
vide a balanced 2-wire or 4-wire, 600 ohm output.
0V
5V
Selectable
Audio
Filter
Volume
Control
Rx Gate
Control
Driver
Amp
Driver
Amp
Mute
Switch
Mute
Switch
Line Level
Adjustment
Transformer
Line
Output
Line
Monitor
Speaker
Output
}