Circuito Audio Tx - Motorola P100 Serie Servicehandbuch

Teoria del funzionamento: Componenti principali
2.2.5

Circuito audio TX

Il circuito audio TX è composto da: microfoni, LPF, Audio Processor IC e sistema sub-toni TX.
LPF di ordine
4 Order LPF
4 (Fc=4 KHz)
(Fc=4KHz)
U501-C,D
U501-C,D
TXA1
TXA1
VR1
VR1
(HPF)
pin
(HPF)
pin4
4
da -6 a +4,5
-6 to +4.5dB/
dB/1,5 dB
1.5dB
Tono IN (dal
Tone IN
CPU)
(from CPU)
LPF di ordine
4 Order LPF
4 (Fc=4 KHz)
(Fc=4KHz)
U501-C,D
U501-C,D
TXA1
TXA1
VR1
VR1
(HPF)
pin
(HPF)
pin4
4
da -6 a +4,5
-6 to +4.5dB/
dB/1,5 dB
1.5dB
Tono IN (dal
Tone IN
CPU)
(from CPU)
Mic
Mic
(Audio IN)
(Audio IN)
Comp- Pre-
Com- Pre-
ressore enfasi
pressor Emphasis
LPF sub-audio
Sub audio
programmabile
Programmable
DTA1
DTA1
LPF
pin 19
pin19
Figura 2-5. Schema a blocchi audio TX (UHF1 e UHF2)
Mic
Mic
(Audio IN)
(Audio IN)
Pre-
Comp-
Com- Pre-
ressore enfasi
pressor Emphasis
LPF sub-audio
Sub audio
programmabile
Programmable
DTA1
DTA1
LPF
pin 19
pin19
Figura 2-6. Schema a blocchi audio TX (VHF)
Audio Processor IC (AK2347)
Audio Processor IC (AK2347)
HPF TX/RX
TX/RX HPF
Scrambler/
Scrambler/
Descrambler
Descrambler
Fc=300 Hz
Fc=300Hz
U102
LPF di ordine
2 (Fc=300
2 Order LPF
da -6 a +6
-6 to +6dB/
KHz)
dB/0,5 dB (Fc=300Hz)
0.5dB
VR5
pin 17
pin17
U502-A
U502-A
Audio Processor IC (AK2347)
Audio Processor IC (AK2347)
HPF TX/RX
TX/RX HPF
Scrambler/
Scrambler/
Descrambler
Descrambler
Fc=300 Hz
Fc=300Hz
U102
LPF di ordine
2 (Fc=300
da -6 a +6
2 Order LPF
-6 to +6dB/
KHz)
dB/0,5 dB
(Fc=300Hz)
0.5dB
VR5
pin 17
pin17
U502-A
U502-A
Limita-
Splatter
VR2
Limiter VR2 Splatter
tore
da -9,6 a +3 Fc=2,55 KHz/
-9.6 to +3dB/ Fc=2.55KHz/
dB/0,2 dB 3 KHz
0.2dB 3KHz
6 Order LPF
6 Order LPF
Amp. AF TX
(Fc=3KHz)
TX AF Amp.
(Fc=3KHz)
Reg.
Mod.Adj,
mod.
U508
U501-A,B
U508
U501-A,B
A VCO e
To VCO &
VCTCXO
VCTCXO
Limita-
VR2
Limiter VR2
tore
Fc=2,55 KHz/
da -9,6 a +3
-9.6 to +3dB/ Fc=2.55KHz/
dB/0,2 dB
0.2dB
6 Order LPF
6 Order LPF
(Fc=3KHz)
(Fc=3KHz)
U502-C
U502-C
U501-A,B
U501-A,B
A VCO e
To VCO &
VCTCXO
VCTCXO
2-7
SMF
SMF
pin 8
pin8
U502-C
U502-C
Splatter
SMF
Splatter SMF
3 KHz
3KHz
pin 8
pin8
Amp. AF TX
TX AF Amp.
Reg.
Mod.Adj,
mod.
U508
U508