Tait TM8000 Series Applications Manual page 82

Audio Paths
Figure 3.14 Receive and transmit audio paths - simplified block diagram
receive audio path
R1
receiver
deviation
demodulator
normaliser
output
transmit audio path
T13
audio to
dev.
transmitter
scaler
modulator
Key:
tap point (tap in or tap out)
LPF low-pass filter
HPF high-pass filter
ALC auto level controlled
Audio
Configuration
Audio Source
82 Programmable I/O Lines
Figure 3.14 shows a simplified block diagram of the receive and transmit
audio paths, the locations of the tap points available, and the tap types.
R2 R4
3kHz 300Hz
LPF HPF
T12 T8
limiter and pre-
3kHz LPF emphasis
tap types:
type A
Bypass In
The audio configuration consists of the following elements:
audio source associated with each PTT (CH_MIC_AUD,
I
AUX_MIC_AUD, AUD_TAP_IN)
Rx/PTT type (Rx, Mic PTT, EPTT1, EPTT2)
I
tap out point (R1, R2, R4, R5, R7, R10, T3, T4)
I
tap out type (C-Bypass Out, D-Split, E-Splice)
I
tap out unmute condition
I
tap in point (T3, T4, T5, T8, T12, T13, R7, R10)
I
tap in type (A-Bypass In, B-Combine, E-Splice)
I
tap in unmute condition
I
For each PTT (Mic PTT, EPTT1 and EPTT2) a different audio source can
be selected. These audio sources are CH_MIC_AUD, AUX_MIC_AUD
and AUD_TAP_IN.
Note
You can allocate an audio tap input at the same time as a micro-
phone input by setting the audio source for a PTT to
CH_MIC_AUD or AUX_MIC_AUD, and defining a tap in and
out point for the same PTT. However, audio samples from the
audio tap input will overwrite those from the microphone input,
unless the tap in type and tap out type are set to 'Splice'.
R5 R7
future
de-
processing
emphasis
option
T5
future
300Hz
processing
HPF
option
type B type C type D
Combine Bypass Out
+
TM8000 3DK Hardware Developer's Kit Application Manual
September 2003 © Tait Electronics Ltd
audible
indicators
R10
audio to
+
volume
control
and speaker
T4 T3
future
processing
option
type E
Split Splice
ALC
mic
audio