TM8000 3DK Hardware Developer’s Kit
Application Manual
Connecting Third-Party Products
109
September 2003
© Tait Electronics Ltd
shows the audio interfacing between the radio and the
encryption module specified in
.
The audio interfaces in
are recommended and best suit
Transcrypt SC20-4xx series encryption modules. This configuration
maximises system flexibility by not excluding other hardware options and
system configurations from being used with encryption. For example, the
encryption module could be used in a radio that is cross-band linked with a
second radio.
Figure 5.6
Encryption module - audio interfacing
deviation
300Hz
de-
future
processing
option
normaliser
3kHz
LPF
HPF
emphasis
audible
indicators
R10
R7
R5
R4
R2
R1
audio to
dev.
transmitter
modulator
pre-
future
processing
option
scaler
limiter and
3kHz LPF
emphasis
ALC
mic
audio
T3
T5
T8
T12
T13
300Hz
HPF
future
processing
option
T4
Key:
tap point (tap in or tap out)
DSP digital signal processor
LPF
low-pass filter
HPF high-pass filter
ALC auto level controlled
+
receive audio path
transmit audio path
+
type A
type B
type C
type D
type E
tap types:
Combine
Bypass Out
Split
Splice
Bypass In
receiver
demodu-
lator
output
audio to
volume
control
and
speaker
decrypt/
encrypt
de-
emphasis
synch
pulse
detect
synch
pulse
inject
Rx in
Tx in
encryption module
2.5
kHz
LPF
AUD_TAP_IN
AUD_TAP_OUT
560
4.7k
DSP
Rx-Tx
audio
switch
DSP
Rx-Tx
audio
switch
pre-
emphasis
300Hz
HPF