User guide

CM52 Integrators’ Manual
CM52 Integrators’ Manual
WI_DEV_CM52_UGD_001-001
Page 30 of 53
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2.6.2 Analog Audio
ATMS is the analog audio input to the Wireless CPU
®
. When it is active, it is connected to the radio
via the audio processing stages in the Wireless CPU
®
.
The AFMS is the analog audio output from the Wireless CPU
®
. When it is active it is connected to
the radio via the audio processing stages in the Wireless CPU
®
.
The AGND is the analog reference signal. ATMS and AFMS are referenced to this signal, which is
connected to GND in one place inside the Wireless CPU
®
.
Pin Signal Description
7 AFMS Audio Output From Wireless CPU
®
10 ATMS Audio Input To Wireless CPU
®
9 AGND Analog Reference
Table 19: CM52 Analog Audio Signals
Signal Parameter
Wireless CPU
®
audio output 300 – 3400 Hz
Output Impedance
Rout 100 Ω
Drive capacity into 10 kΩ
3.77 V
P-P
max. or 2.5 dBV
External Device audio input
impedance
Zin ≥ 10 kΩ
Volume control -81 dB from maximum > - 81 dB (mute)
AFMS
Sensitivity 1004 Hz tone at 8kHz deviation
generates 900+100 mV
rms
.
Sources are preferably AC
coupled.
Cout ≥ 2.2uF
External Device audio source
Output resistance
Rout ≤ 1.0 kΩ
Wireless CPU
®
audio input
impedance
Zin ≥ 10 kΩ
Levels from external audio source
(maximum)
3.77 V
P-P
max. or 2.5 dBV
ATMS
Sensitivity 1004 Hz tone at 900+100 mV
rms
generates 8kHz deviation.
Table 20: Audio Characteristics