Local Oscillation Mode; Set The Basic Testing Parameter - Deepace KC901V Manual

Single sweeping mode. Instrument sweeps only once with each RUN/STOP
press.
continuous sweeping mode. Instrument will do the constant sweeping. In
the single sweep mode, this sign will also be shown while sweeping.
Stop sweeping. RF circuit's power will be cut entirely.
If the main setting parameters are changed when not sweeping, instrument will
scan once automatically.
Attention
Since there is no warm-up, result is not accurate in the single sweeping mode.
it's only suitable for qualitative analysis. When accurate data is needed, instrument
must be set to continuous sweeping mode.

2.6 Local Oscillation Mode

There is a Local oscillation mode in each of the following modes: SPEC, S21 and
FIELD. This function is for judging signal imaging.
LowLo: Low local oscillation. The LO frequency lower than the test frequency.
The image interference is from low frequency side.
HighLo: High local oscillation. The LO frequency is higher than the test frequency.
The image interference is from the high frequency side.
If there is a signal showing in the same position on the screen whether in LowLo
mode or HighLo mode, this signal is probably a truly existed signal. If it shows in Low-
Lo mode but disappears in HighLo mode, the real frequency probably is 219.3MHz
less than the one that is shown. If it shows in HighLo mode but disappears in LowLo
mode, the real frequency probably is 219.3MHz more than the one that is shown.
When the frequency is lower than 200MHz, the local oscillation setting is invalid.
In this case, image interference can be filtered through low-pass selector.
Attention
The factory calibrations of spectrum, transmission and field strength modes are
done in HighLo mode. The test may be inaccurate under LowLo mode.
2.7 Basic Testing Parameters Setting
To set the central frequency, press CENT first, then enter it on the number pad.
If the desired frequency is near the current frequency setting, user might use the
hand wheel or press "+" "-".
To set the sweeping width, press SPAN.
To set the start frequency (START), use the combined key SHIFT+CENT.
To set the stop frequency (STOP), use the combined key SHIFT+SPAN.
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