7.12.5
Press
〖
ModuDepth
〗
softkey to select “modulation depth” and set it to 50
％
by using numeric keys or
knob.
After setting, generator outputs PWM modulating waveform with the parameters.
8.1 Frequency-shift keying (FSK)
PeakTech
®
4035
In digital communication and the system of remote control and remote measurement, the transmitting of
digital signal usually use FSK or PSK, and the frequency or the phase of carrier wave is modulated by
coding. The original digital signal is reverted via modulator in the receiver.
Pressing the key of (Keying) and selecting “CHA FSK”, FSK signal will be output from the port of “output A”.
In the graph of FSK waveform on the top left of the screen, the frequency is that of carrier wave or hop
frequency alternately. The interval time of alternating of the two frequencies can be also settled.
8.1.1 Setting of carrier frequency
: Pressing the key of (Option 1) and selecting “carrier f”, the carrier
frequency will be changed to green. It can be settled by the keys or by the knob. For FSK modulation, signal
of channel A is taken as carrier signal and the carrier frequency is the first frequency of the signal of channel
A.
8.1.2 Setting of hop frequency
: Pressing the key of (Option 3) and selecting “Hop Freq”, the hop
frequency will be changed to green. It can be settled by the keys or by the knob. Hop frequency is the
second frequency of the signal of channel A.
8.1.3 Setting of interval time
: Pressing the key of (Option 4) and selecting “Interval”, the interval time
value will be changed to green. It can be settled by the keys or by the knob.
8.2 ASK modulation
Pressing the key of (Keying) and selecting “CH ASK”, ASK signal will be output from the port of “output A”.
In the graph of ASK waveform on the top left of the screen, the amplitude is that of carrier wave or hop
amplitude alternately. The interval time of alternating of the two amplitudes can be also settled.
8.2.1 Setting of carrier amplitud
e: Pressing the key of (Option 2) and selecting “Carrier F”, the carrier
amplitude will be changed to green. It can be settled by the keys or by the knob. For ASK modulation, signal
of channel A is taken as carrier signal and the carrier amplitude is the first amplitude of the signal of channel
A.
8.2.2 Setting of hop amplitude
: Pressing the key of (Option 3) and selecting “Hop Ampl”, the hop
amplitude will be changed to green. It can be settled by the keys or by the knob. Hop amplitude is the
second amplitude of the signal of channel A.
The difference between carrier amplitude and hop amplitude may be very large. Fixed attenuation of 0dB is
used for channel A so as to avoid the frequent switch of relay in the auto mode.
8.2.3 Setting of interval time
: Pressing the key of (Option 4) and selecting “Interval”, the interval time
value will be changed to green. It can be settled by the keys or by the knob.
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