Codan Radio Communications VT-3-150-SN User Manual
Audio Processor Board Instruction Manual
6-1
6
TEMPERATURE COMPENSATION
The FM Audio Processor includes temperature compensation circuitry to maintain constant
transmitter audio deviation with a fixed level input signal. It is capable of not only compensating for
temperature related level variations within the FM Audio Processor (typically –0.3 to –0.5 dB at
–40C) but can also compensate for changes caused by the synthesizer or crystal oscillator module
that is not equipped with its own temperature compensation.
transmitter audio deviation with a fixed level input signal. It is capable of not only compensating for
temperature related level variations within the FM Audio Processor (typically –0.3 to –0.5 dB at
–40C) but can also compensate for changes caused by the synthesizer or crystal oscillator module
that is not equipped with its own temperature compensation.
The factory specification is as follows:
Wideband
When a 2.4 kHz tone is applied at a level of –8dBm to the balanced input of the transmitter, the
transmitter deviation shall be ±4.8 kHz at room temperature and can vary from ±4.5 kHz to
±5.0 kHz from -40ºC to +60ºC.
transmitter deviation shall be ±4.8 kHz at room temperature and can vary from ±4.5 kHz to
±5.0 kHz from -40ºC to +60ºC.
Narrowband
When a 2.4 kHz tone is applied at a level of –8 dBm to the balanced input of the transmitter, the
transmitter deviation shall be ±2.4 kHz at room temperature and can vary from ±2.25 kHz to
±2.5 kHz from -40ºC to +60ºC.
transmitter deviation shall be ±2.4 kHz at room temperature and can vary from ±2.25 kHz to
±2.5 kHz from -40ºC to +60ºC.
Since the specifications of the components used in the synthesizer or oscillator may change over
time, changes to the temperature compensation circuit may be necessary even for the same type of
equipment.
time, changes to the temperature compensation circuit may be necessary even for the same type of
equipment.
Contact the factory for more information on values used.