Aeroflex 3901 - Page 43

Test Set Operation
Subject to Export Control, see Cover Page for details.
3-9
MIC/ACC Connector
The Microphone and accessory connector is an 8 pin DIN connection with ring-lock.
This connector provides EXT MOD input (alternative to AUDIO IN 2/EXT MOD BNC) and DEMOD
OUT (analog system). This connector can be used to connect a microphone, headset, or
speaker. The Connector accepts a PTT (Press To Talk) microphone for testing simplex trunked
radios.
There is provision to enable/disable the EXT MOD input by an external switching circuit.
Audio 1 and 2 IN Connectors
AUDIO IN 1 and 2 are the primary AF input and external modulation input connectors. The
Connectors can be configured as high impedance or 600 Ω unbalanced.
AUDIO IN 1 and AUDIO IN 2 can be jointly configured as 600 Ω balanced for AF IN only, in which
case AUDIO IN 2 is not available for EXT MOD. The MIC/ACC Connector
can be used for EXT
MOD IN if required.
FCTN GEN/DEMOD Connector
(Function Generator and Demodulated Signal Output)
This is the primary AF GEN output. The Connector can be configured as DEMOD OUT, as an
alternative to MIC/ACC Demod out. When this arrangement is used the audio generators are
unavailable. The Connector can also be used for Demod Audio, Audio 1, Audio 2 or MIC.
Changing configuration to DEMOD OUT while still connected to the MIC/AF Input of a radio
under test may create a feedback loop.
Scope CH1/CH2 Connectors
The Scope CH1 and CH2 connectors are the signal input connectors for the Oscilloscope
function. The Source selection drop-down menu on the Vertical Settings Tile of the Oscilloscope
controls the routing of signals from these connectors.
The Scope CH1 and CH2 connectors are the dedicated inputs to the dual-trace oscilloscope
providing a maximum input rating of 100 Vpeak. Depending on the System selected, the
oscilloscope also obtains input from the audio input or demodulated signals without using the
dedicated inputs.
Test Connector
Reserved for future development.
Do not connect a VGA monitor to this connector.
USB Connector
The front panel USB connector is a USB standard connection that allows connection of USB 1.1
devices (e.g. a USB memory stick or Network connectors). Recommended USB memory device
is Aeroflex PN 7110-1100-400. The Front Panel USB Connector is only found on the 3920 Test
Set.