Audio Processor
4
MX806A
2 Signal List
Pin
Signal
Description
1
The output of the 4.032MHz on-chip clock oscillator. External components are
required at this output when a Xtal is used. See Figure 2.
Xtal
2
3
4
Xtal/Clock
The input to the on-chip 4.032MHz clock oscillator inverter. A 4.032MHz Xtal or
externally derived clock should be connected here. See Figure 2. This clock
provides timing for on-chip elements, filters, etc.
Serial Clock
Command Data
This is the ‘C-BUS’ serial Clock input. This clock, produced by the
microcontroller, is used for transfer timing of commands and data to and from the
MX805A. See Section 6 and Section 7.1.4.
This is the ‘C-BUS’ serial data input from the microcontroller. Command Data is
loaded to this device in 8-bit bytes, MSB (bit 7) first and LSB (bit 0) last,
synchronized to the Serial Clock. The Command/Data instruction is acted upon
at the end of loading the whole instruction. Command information is detailed in
Table 3 through Table 7. See Section 6 and Section 7.1.4.
5
CS
Chip Select . This is the ‘C-BUS’ data loading control function. This input is
provided by the microcontroller. Command Data transfer sequences are initiated,
completed or aborted by the CS signal. See Section 6 and Section 7.1.4.
6
7
8
VOGAD OUT
RX Audio In
VOGAD In
The error-voltage output of the selected VOGAD sensor. This output, with
external attack and decay setting components, should be connected as in Figure
2 and Figure 3, to the VOGAD In pin.
The audio input to the MX806A from the radio receiver’s demodulator circuits.
This input, which requires AC coupling with capacitor C12, is selected via a
Control Command bit.
The gain control signal from the selected VOGAD sensor (VOGAD Out) to the
Input Process voltage-controlled amplifier. The required sensor is selected via a
Mode Command. The choice of two sensors enables gain control from either the
Input Process or an External Process. External attack and decay setting
components should be applied as recommended. See Figure 2 and Figure 3.
9
V
BIAS
The output of the on-chip analog circuitry bias system, held internally at V /2.
DD
This pin should be decoupled to V by capacitor C10. See Figure 2.
SS
10 Mic In (+)
11 Mic In (-)
The non-inverting input to the microphone Op-Amp. This input requires external
components for Op-Amp gain/attenuation setting as shown in Figure 2.
The inverting input to the microphone Op-Amp. This input requires external
components for Op-Amp gain/attenuation setting as shown in Figure 2.
12
V
SS
Negative Supply (GND)
13 Mic Out
The output of the Microphone Op-Amp, used with the Mic In (-) input to provide
the required gain/attenuation using external components as shown in Figure 2.
The external components shown are to assist in the use of this amplifier with
wither inverting or non-inverting inputs. During Powersave (Volume Command
this output is placed at V .)
SS
14 Processed Audio In The input to the device from such external audio processed as Voice Store and
Retrieve or Frequency Domain Scrambling. This input, which requires AC
Coupling with capacitor C13, is selected by a Mode Command bit.
15 External Audio
Process
The buffered output of the Input Processing Stage. Its purpose is to further
external audio processing stages prior to re-introduction at the Processed Audio
In Pin.
16 Calibration Input
A unique audio input to be used for dynamic balancing of the modulator drives for
measuring Deviation Limiter levels. A CUE (beep) input from the MX803 Audio
Tone Processor can be entered on this line. This audio input must be externally
biased. It is selected via a Mode Command bit.
17 Main Process Out
The output of the Main Process stage. This output should be mixed with any
additional system audio inputs (Audio, Sub-Audio Signaling, MSK) in the on-chip
Modulation Summing Amplifier. External components shown in Figure 2 should
be used as required.
ꢀ1998 MX-COM, Inc.
www.mxcom.com Tel: 800 638 5577 336 744 5050 Fax: 336 744 5054
Doc. # 20480064.006
4800 Bethania Station Road, Winston-Salem, NC 27105-1201 USA
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