CIRCUIT DESCRIPTION
5-22
Figure 5-5 Audio Circuit Block Diagram
RF Board
UI Board
U17B
Diff-Single
Converter
Tones Buffer
Tone Sig
Combiner
U17A
U17C
U8
U21
Internal
Speaker Amp
External
Speaker Amp
Volume
Control Amp
U18
Internal Spkr
Mute
External
Spkr Mute
Mute A
Mute B
Single-End
Control
nSEOP
To Acc Jack (UDC)
Pins 2, 6
SPx
8 ohms
Q8
Q10
Q2
Rx Audio Mute
J2-38
PD4
3.3V
Top Panel
Volume
Control
Volume Lev
Buffer
U20
A/D
Converter
Volume Data
Volume Data
D/A
Converter
U9
U7
DC
Vol Level
Logic Board
ADSIC
U2
DSP
U1
SDO
SDO
Mute
Single-Diff
Converter
Mute
Switch
U9
U8A/B
U5A
Rx Signal Data
(SBI/DIN/DIN*/ODC)
Rx
Audio
U1
Microcontroller
PA4
Buffer
Buffer
External Mic In From
Acc Jack (UDC) Pin 3
Microphone
MKxx
U19C
U19B
Int/Ext Mic
Sel Sw
U24
SRC_SEL
Single-Diff
Converter
U19A/D
Audio_In_M
Audio_In_P
Diff-Single
Converter
MAI
U8C/D
Modulation In
VVO
14
converted to serial data which is fed to microcontroller
U1. This allows the microcontroller to determine the
volume level that is currently set by the user.
To set the volume level, the microcontroller then
programs D/A converter to produce a DC output
voltage that sets the desired volume level. This
arrangement allows the microcontroller to totally
control the volume level. The volume control voltage
is then buffered by U18 and applied to the volume
control pin (Vin) of audio amplifiers U8 and U21.
Q8 is connected to the Head Phone Sense pin (2)
of amplifier U21. When Q8 is turned off by the
nSEOP signal, pin 2 goes high and U21 switches from
the differential to the single-ended output mode. This
allows an external speaker-microphone to be
connected from pin 7 to ground instead of across pins
7 and 5.
5.11.2 TRANSMIT AUDIO CIRCUIT
NOTE: A block diagram of the audio circuit is shown
in Figure 5-5.
In transmit mode, the audio for transmission can
be selected from either the internal microphone or an
external microphone connected to pin 3 of the acces-
sory (UDC) connector. Supply voltage is applied to the
internal microphone through R76 with C44 providing
DC blocking. U19B provides buffering and low-pass
filtering. U18C and related components provide the
same function for the external microphone signal.
Analog switch U24 selects either the internal or
external microphone signal, depending on the logic
level on the CS input. The internal microphone NC pin
(4) is selected when CS is low and the external micro-
phone NO (6) is selected when it is high. Q6 provides
inversion and buffering of the SRC_SEL signal.
The single-ended microphone signal is then
converted to a differential signal by U19A and U19D
to reduce noise. It is then fed to the logic board on the
AUDIO_IN_P/M lines, converted back to a single-
ended signal by U8C and U8D, and applied to the
MAI (Microphone Audio In) pin of ADSIC U2.
AUDIO CIRCUIT (VERSION A/B)
Содержание 5100 Series
Страница 76: ...PARTS LIST 7 20 MP032 MP030 A200 Part of A200 Part of A200 MP031 MP033 MP034 A100 A030 EP031 J4 J3 EP030 6 ...
Страница 85: ...8 9 Version C Board see Section 1 13 VHF RF BOARD VER C LAYOUT ...
Страница 87: ...8 11 VHF RF BOARD SCHEMATIC VER B PAGE 2 OF 3 ...
Страница 88: ...8 12 VHF RF BOARD SCHEMATIC VER B PAGE 3 OF 3 ...
Страница 95: ...8 19 BOTTOM VIEW TOP VIEW Version C Board see Section 1 13 UHF RF BOARD VER C LAYOUT ...
Страница 105: ...8 29 BOTTOM VIEW TOP VIEW 700 800 MHZ RF BOARD VER C LAYOUT Version C Board see Section 1 13 ...
Страница 112: ...8 36 SEM Module 5500 120 LOGIC BOARD VER C SCHEMATIC PAGE 5 OF 11 ...
Страница 113: ...8 37 Analog Switch 5500 120 LOGIC BOARD VER C SCHEMATIC PAGE 6 OF 11 ...
Страница 118: ...8 42 5500 120 LOGIC BOARD VER C LAYOUT BOTTOM VIEW TOP VIEW Version C Board see Section 1 13 ...
Страница 127: ...8 51 5100 160 LOGIC BOARD VER B TOP VIEW 5100 160 LOGIC BOARD VER B BOTTOM VIEW Version with Motorola UCM ...
Страница 143: ...8 67 5500 420 USER INTERFACE BOARD VER C TOP VIEW Version C Board see Section 1 13 ...
Страница 144: ...8 68 5500 420 USER INTERFACE BOARD VER C BOTTOM VIEW ...
Страница 147: ...8 71 5100 410 USER INTERFACE BOARD VER A TOP VIEW Version w o encryption module Version A Board see Section 1 13 ...
Страница 148: ...8 72 5100 410 USER INTERFACE BOARD VER A BOTTOM VIEW Version w o encryption module ...
Страница 151: ...8 75 5100 450 USER INTERFACE BOARD VER B TOP VIEW Version with EFJ SEM Version B Board see Section 1 13 ...
Страница 152: ...8 76 5100 450 USER INTERFACE BOARD VER B BOTTOM VIEW Version with EFJ SEM ...
Страница 155: ...8 79 5100 460 USER INTERFACE BOARD VER B TOP VIEW Version with Motorola UCM Version B Board see Section 1 13 ...
Страница 156: ...8 80 5100 460 USER INTERFACE BOARD VER B BOTTOM VIEW Version with Motorola UCM ...
Страница 171: ...9 14 OBSOLETE VERSION 5100 410 USER INTERFACE BOARD VER A TOP VIEW Version A Board see Section 1 13 Revision 6 Board ...
Страница 172: ...9 15 OBSOLETE VERSION 5100 410 USER INTERFACE BOARD VER A BOTTOM VIEW Revision 6 Board ...
Страница 173: ...Part Number 001 5100 0017CD 12 04hph Printed in U S A ...