Different CW power displayed in Full Span compared to 1/2, 1/4, etc.
Greetings all, what a great product!
I need to use the V6 for CW power measurement and noticed that when I connect a signal generator, the displayed CW (peak) power is different between full span and the fractional spans. Specifically, the reported power in fractional span modes is very accurate. However, in the full span mode, the displayed power is about 16dB less. I would be OK with this, however, I wanted to confirm if this offset is constant and whether there is a way to calibrate it out.
Cheers.
The accuracy is the same but for sure you are measuring in the center which is a bad idea in full span mode since that is where the DC is located.
Simply change the frequency a bit away from the center and the measurement will be perfect.
Why is this the case?
The SPECTRAN V6 is a direct conversion spectrum analyzer (a type of spectrum analyzer that directly converts the input signal to baseband frequency for analysis).
One of the main issues with a direct conversion spectrum analyzer is the presence of the center frequency. In this type of analyzer, the center frequency is directly mixed down to baseband, resulting in a DC (zero-frequency) component in the output spectrum.
The DC component manifests as a peak at the center frequency, causing a significant spike that may obscure or distort nearby spectral components of interest.
We are using some filtering, calibration, and signal processing algorithms to reduce or remove the DC offset and minimize its impact on the accuracy and resolution of the spectrum measurements as best as we can but it will never be perfect in full span mode.
Great, thanks for the help.
