Audio Processor
EXTERNAL INTEGRATION COMPONENTS
R5
VOGAD
IN
C8
8
R6
R12
MX806A
V
DD
V
SS
VOGAD
OUT
HI PEAK
DETECTOR
MIC. OUT
MIC. IN
MIC. IN
TX
DRIVES
-
+
VOGAD
(Voltage Controlled)
AMPLIFIER
TX
HI
- LO PEAK
DETECTOR
MAIN PROCESS
CAL
INPUT
TX INPUT PROCESS
To EXTERNAL AUDIO PROCESSES
ä
RX
DRIVE
PROCESSED AUDIO IN
Figure 3: VOGAD Sensors and Timing Components (from Figure 5)
VOGAD attack and decay times are set using the external components shown in Figure 2 and Figure 3. They
are calculated as described below.
4.2.1
VOGAD Components Calculations – Figure 2 and Figure 5
Provided R5
1.0k and R6
R12
R5
Then
Attack Time (T
A
)
R5 x C8
Decay Time (T
D
)
R6 x C8
2
4.3
4.3.1
Calibration Methods
TX Calibration: From Mic. In to Modulator Drives Out
To effectively null all internal IC tolerance, the following initial calibration routine is suggested.
Disable Peak Detectors (Mode Command)
Set Transmitter Drives to 0dB (Mod. Levels Set)
Pre-emphasis may be employed as required (Control Command)
Set Input Level Amp to 0dB Control Command)
1. Mic. In = 250mVRMS at 1kHz. Set Process Gain Amp for output of 1440mV
P-P
(100% deviation).
2. With Process Gain Amp set as 1 and with Mic. In = 25mV
RMS
at 1kHz, set the Input Level Amp for an
output level of 308mV
RMS
(60% deviation)
4.3.2
RX Calibration: From RX Audio In to Audio Out
Set Audio Output Drive In to Audio Out
Leave Process Gain Amp set as 1 (See Section 4.3.1)
3. With and RX Audio In level of between 154mV
RMS
and 308mV
RMS
(See Section 7) at 1kHz, set the Input
Level Amp for and output level of 308mV
RMS
.
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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