Modulation Menu
When no span for sweeping is selected the output can be modulated according to a limited set of formats.
NONE sets no modulation
AM 1kHz sets an AM modulation. Depth is about 50% and the tone is about 1kHz.
AM 10Hz sets an AM modulation. Depth is about 50% and the tone is about 10Hz.
NFM sets narrow FM modulation. Width is about 3kHz and the tone is about 1kHz.
WFM sets wide FM modulation. Width is about 300kHz and the tone is about 1kHz.
EXTERNAL disables the internal LO driving the mixer and enables the high input as mixer LO input. Minimum external LO input frequency is 5MHz.
The AM and FM modulation is done using a 5 point approximation of a sinus. This limited approximation does contain harmonics and has some steep level steps as can be seen in this measurement of the AM modulation
In the EXTERNAL modulation mode a second tinySA working as a spectrum analyzer in low input mode and outputting its LO from its high connector enabled by setting the LO OUTPUT can drive the mixer of the tinySA in low output mode. By setting the frequency to zero Hz the output will follow the sprectrum analyzer with zero Hz offset and can be used a tracking generator.
Make sure you enable the LO output in CONFIG/EXPERT CONFIG
The settings for the tracking generator tinySA
First normalize the tinySA so you have a clean 0dB level
And then you can connect a filter and do a wide scan
Or do a narrow scan
The dynamic range in this setup is limited due to the reverse leakage thru the mixers. Best would be to add an attenuator and amplifier between the LO output and the tracking generator input to stop the leakage. If you use a external mixer you can set the TG to an offset allowing measurement of the conversion loss of a mixer.
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