Read Panasonic DP-130 / DP-150 Other Service Manuals online
15
3.Line Monitor Circuit
The Line Monitor Circuit consists of an operational amplifier, analog master and its peripheral circuits.
Its function is to monitor the dial tone, DTMF tone, response signals, etc. over the speaker. It also
sounds the output of the key touch tones, alarm tones, etc. from the panel CPU over the speaker. The
received signal from the Ain (M) passes through an AGC circuit and is conditioned by the Analog Front-
End DSP and is then input to the Analog SW2 for volume control. The signal is then input to the
Speaker Amplifier, where it is amplified to a level sufficient to drive the speaker. The key touch tones
and Buzzer Signals from the panel are input to the Analog SW2 for volume control and then input to the
Speaker Amplifier. The monitor tone from the phone line and the buzzer tone from the panel can be
adjusted from the Control Panel.
HYSIG
RX signal
TX signal
Hybrid Circuit
Speaker
Amplifier
Electronic Volume
Analog SW2
Buzzer Signal from Panel
AGC
Analog SW1
Gain Switch
Amplifier
Ain(M)
Aout(M)
Aout(V)
Analog Front-End DSP
LPF Fc:4.5KHz
LPF Fc:7.8KHz
HYBSR
Analog Master
IC906
Click on the first or last page to see other DP-130 / DP-150 service manuals if exist.