Codan Radio Communications VT-3-150-SN User Manual
2-8
Transmitter Main Board Instruction Manual
2.2
MT-3 Front Panel Board
The MT-3 Front Panel Board is a subsection of the MT-3 Transmitter Board which is used to
mount the front panel switch, diode, and microphone connector. The main purpose of the board is
to eliminate a wiring harness for the front panel components. Jumper J1, located on the rear of the
circuitboard, is used to select whether or not the MIC PTT line activates the transmitter's TOT.
Jumper J2 is used to select whether or not Rx Audio or 13.8 Volt is supplied to pin 4 of the
microphone.
mount the front panel switch, diode, and microphone connector. The main purpose of the board is
to eliminate a wiring harness for the front panel components. Jumper J1, located on the rear of the
circuitboard, is used to select whether or not the MIC PTT line activates the transmitter's TOT.
Jumper J2 is used to select whether or not Rx Audio or 13.8 Volt is supplied to pin 4 of the
microphone.
• Jumper J1:
'x' position
MIC PTT NTO no time-out-timer (factory setting)
'y' position
'y' position
MIC PTT WTO with time-out-timer
• Jumper J2:
'x' position
Rx Audio enabled to MIC-4 pin (factory setting)
'y' position
'y' position
+13.8 Volts supplied to MIC-4 pin
Refer to section 5.3.2 "MT-3 Front Panel Board Schematic Diagram".
2.3
MT-3 Audio Processor (Version 1.6)
invisible text
2.3.1 General
The MT-3 Audio Processor is a versatile circuitboard that can provide several types of audio
processing for voice or data transmission. Two analog switches on the audio processor, controlled
by a common signal, make it possible to transmit voice or data. A continuous +9.5 Vdc supply
and a switched +8.0 Vdc supply are required to power the module. The MT-3 Audio Processor is
backwards compatible to Daniels Electronics MT-2 series transmitters. Refer to section 5.4.1
"MT-3 Audio Processor Component Layout" and to section 5.4.2 "MT-3 Audio Processor
Schematic Diagram" for component location and designation references.
processing for voice or data transmission. Two analog switches on the audio processor, controlled
by a common signal, make it possible to transmit voice or data. A continuous +9.5 Vdc supply
and a switched +8.0 Vdc supply are required to power the module. The MT-3 Audio Processor is
backwards compatible to Daniels Electronics MT-2 series transmitters. Refer to section 5.4.1
"MT-3 Audio Processor Component Layout" and to section 5.4.2 "MT-3 Audio Processor
Schematic Diagram" for component location and designation references.
2.3.2 Power Requirements
The audio processor can be configured for continuous audio standby or for switched audio standby
by the Transmitter Main Board. If fast audio risetime is desired, the transmitter should be operated
in standby mode 2 or 3 as specified in section 2.1.2.7. Power for the microphone input and the
balanced input can be separately disabled by jumpers J3 and J4 respectively if the input is not
required. This results in a current savings of approximately 11 mA per input. The current
requirements for the MT-3 Audio Processor are shown in Table 2-1. The current for the associated
TOT is approximately 4 mA when the transmitter is keyed and is included in the keyed values in the
table below.
by the Transmitter Main Board. If fast audio risetime is desired, the transmitter should be operated
in standby mode 2 or 3 as specified in section 2.1.2.7. Power for the microphone input and the
balanced input can be separately disabled by jumpers J3 and J4 respectively if the input is not
required. This results in a current savings of approximately 11 mA per input. The current
requirements for the MT-3 Audio Processor are shown in Table 2-1. The current for the associated
TOT is approximately 4 mA when the transmitter is keyed and is included in the keyed values in the
table below.