RELM Communications Inc SRU50ABC ユーザーズマニュアル
S Series Repeater USER MANUAL
©RELM Communications Inc. Revision 1.0
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Channel Spacing: May also be referred to as the synthesizer step. As a rule the oscillator frequency must be
integer divisible by the modulo value and then the step size. The step size is usually set to half that of the channel
spacing.
integer divisible by the modulo value and then the step size. The step size is usually set to half that of the channel
spacing.
Accel Proportion: Controls the degree of speedup at the onset of PTT.
Accel Integral: Controls the multiplication factor of the Accel Proportion.
For further information and reading, you may refer to the Philips Semiconductor Data Book for the SA7025DK chip.
Modulation Control
DC-FM uses two point modulation and its parameters can be set by the following:
VCO Deviation: The digital pot value sets the modulation level fed to the VCO's modulation input. A value of 0
sets the minimum deviation level. A value of 255 sets the maximum deviation level.
sets the minimum deviation level. A value of 255 sets the maximum deviation level.
Reference Bias: The digital pot value sets the center carrier frequency of the transmitter frequency. A value of 0
sets the highest carrier frequency. A value of 255 sets the lowest carrier frequency. A value around 128 is normally
used. If the value is to high or too low this may result in unsymmetrical modulation distortion due to the limited
range of the master reference oscillator.
sets the highest carrier frequency. A value of 255 sets the lowest carrier frequency. A value around 128 is normally
used. If the value is to high or too low this may result in unsymmetrical modulation distortion due to the limited
range of the master reference oscillator.
Reference Level: The digital pot value sets the modulation level fed to the master reference oscillator. A value of 0
sets the minimum deviation level. A value of 255 sets the maximum deviation level. It primarily is used to set the
modulation balance at low frequencies.
sets the minimum deviation level. A value of 255 sets the maximum deviation level. It primarily is used to set the
modulation balance at low frequencies.
Transmit RF Power Output
Transmit Power: The digital pot value sets the RF drive level to the power amplifier. A value of 0 sets the
transmitter power to minimum. A value of 255 sets the transmitter power to maximum.
transmitter power to minimum. A value of 255 sets the transmitter power to maximum.
CTCSS Control
Tx Subtone: Enters directly the frequency of the transmitter's modulation encoder.
Rx Subtone: Enters directly the frequency for the receiver's decoder to operate.
Tx Subtone Level: This value controls the level of the transmitter's modulation encoder. Steps are 0.85dB.
Channel selection
Three methods are available for channel selection.