TECHNICAL DESCRIPTION AND OPERATING MANUAL ST131 <PIRANHA II> and ST131N
23
3.3 DEMODULATION MODE
This mode is intended mainly for demodulation and audio control of the investigated
signal.
Input and output this mode carried out by pressing
. In this case, the cursor lines appear to indicate
the demodulation bandwidth (Figure 21). Sound control indication enables, too (
changes to ).
To listen this signal set the desired volume level by rotating the volume control (position 3, Figure
2). Using headphones is preferable.
1. Type of demodulation.
2. Demodulation bandwidth.
CONTEXT BUTTON FUNCTIONS______________________________________________
– access to selection of demodulator type. Possible selection includes amplitude modulation
(АМ), frequency modulation (FM), single sideband modulation with lower (LSB) and upper (USB)
sideband.
–
- selection of demodulation bandwidth. Bands from 2 KHz to 500 KHz are available
for sound (audible) control. The 5 MHz band provides only viewing demodulated signal in the time
domain (it is necessary to press on
). This is useful, for example, for identifying an analog video
signal.
-
selection of the frequency step value for fine tuning. Step can be from 1 Hz to the selected
bandwidth.
- access to fine tuning the central frequency. If selected, it is highlighted in red
. Tuning is
performed by using the rotary knob by 100 Hz step.
Going to the waveform of the demodulated signal by pressing on
. Back in the spectrogram –
pressing second time
.
Figure 21
