November 16, 2006
6881094C31-E
3-38
The other clock supplied to the Patriot IC is a 32.768 kHz square wave. This clock is generated by
the Flipper IC internal oscillator and an external 32.768 kHz crystal Y301 and is connected to the
Patriot IC CKIL pin.
3.2.5
VOCON Audio Paths
This section describes the VOCON transmit and receive audio paths.
VOCON Audio and DC Circuits,” on page 8-101
for schematic details of the following discussion.
3.2.5.1 Transmit Audio Path
. The internal microphone audio enters the VOCON board through the universal
connector J101 pin 36, and the internal microphone bias is set by circuitry that includes R531, R533,
C519 and C521. The internal microphone signal is connected to the MICIN_NEG pin, which is the
input terminal on the GCAP II IC internal op-amp A3. The gain of the A3 op-amp is set by the values
of R540, R555, and the resistance of EEPOT U509 (digital potentiometer), which is programmed by
Patriot IC GPIO lines.
The external microphone audio enters the VOCON board through the universal connector J101 pin
13, and the external microphone bias is set by circuitry that includes R563, R565, C547, and C548.
The external microphone signal is connected to the AUX_MIC_NEG pin, which is an input terminal
on the GCAP II IC internal op-amp A5. The gain of the A5 op-amp is set by the values of R566,
R561, and the resistance of the EEPOT U509.
The Patriot IC, through the SPI bus, programs a multiplexer to select one of the microphone signals.
Then, the selected amplified microphone signal goes through a programmable gain amplifier before
it goes to the CODEC for A/D conversion. The resulting digital data is filtered and sent to the DSP on
the SAP CODEC_TX line from the GCAP II IC TX pin. After additional filtering and processing, the
DSP sends the data-out from the STDB pin to the RF interface connector P201 pin 4 (TX_DATA),
which is connected to the DAC U203 on the transceiver board.
Figure 3-13. VOCON Transmit Audio Path
TP214
INTERNAL MIC
Bias (R531,
R533, C519, C521)
and Input
(R540, C522)
EXTERNAL MIC
Bias (R563,
R565, C547, C548)
and Input
(R566, C549)
GCAP II IC U501
EEPOT U509
0 - 50K, 256 taps
MIC PREAMP
A3
Gain =
-14dB to 16dB
MIC PREAMP
A5
Gain =
-14dB to 16dB
EEPOT U509
0 - 50K, 256 taps
MUX
PGA
-7 to +8dB
in 1dB steps
Set at 6dB
CODEC A/D
13-bit
HP FILTER
cutoff = 200HZ
LP FILTER
cutoff = 3.5KHZ
Patriot GPIO
PB4, PB5,
PB6, PB7
Patriot SPIB
Patriot SAP/BBP
Flipper
U301
RF D/A
U203
(On RF Board)
TX_SSI_FSYNC
TX_SSI_CLK
TX_DATA
CODEC_FSYNC
CODEC_DCLK
CODEC_TX
GCAP_CE, SCKB
SPI_MISOB
SPI_MOSIB
AUX_OUT
R561
MIC_OUT
R555
4
EEPOT_CS_EXT*
EEPOT_CS*
EEPOT_U_D*
EEPOT_INC*
4
3
MICIN
_NEG
AUX_MIC
_NEG
MAEPF-27418-A
Summary of Contents for ASTRO XTS-5000
Page 7: ...vi Table of Contents November 16 2006 6881094C31 E Notes ...
Page 11: ...x List of Figures November 16 2006 6881094C31 E Notes ...
Page 17: ...November 16 2006 6881094C31 E xvi CommercialWarranty Notes ...
Page 31: ...November 16 2006 6881094C31 E xxx Portable Radio Model Numbering System Notes ...
Page 83: ...November 16 2006 6881094C31 E 3 44 Theory of Operation Encryption Module ...
Page 135: ...November 16 2006 6881094C31 E 5 44 Troubleshooting Charts Secure Hardware Failure Notes ...
Page 175: ...November 16 2006 6881094C31 E 7 32 Troubleshooting Tables List of Board and IC Signals Notes ...
Page 367: ...November 16 2006 6881094C31 E Glossary 10 Notes ...
Page 373: ...Index 6 November 16 2006 6881094C31 E Notes ...