Hello.
I am a beginner and would like some advice. My measurements: i measure external oscillator 1khz and active notch.
There is 2Vrms at the oscillator output. Notch has a gain of 46dB
Measuring oscillator with notch. Notch with weighting.
The first post was the last measurement.
1st step
Measuring the oscillator itself. There is 2Vrms at the oscillator output
The oscillator shows 4.72dBV, so 1.72Vrms, not 2Vrms.
The notch attenuates, so its gain is negative dB, and appears to be more like -70dB at best, not clear what the attenuation at 1kHz is precisely though, but the 4th step shows the 1kHz tone is down by 68.44dB, which is close to 70dB attenuation.
I am not sure exactly what setup was used for each graph, but the 1st graph appears to be either the raw oscillator, or could be the oscillator with notch and then the notch weighting applied to correct for it. 4th step is oscillator with notch and no weighting I think?
So I am not clear where the 46dB figure comes from?
Hello Mark
Hello
Sorry, I made a bit of a mess in the pictures. Post number 1 is 4 step.
The connection during measurement is written in the upper part of the picture.
The notch is active, see diagram. The gain is given by the ratio of resistances R2 and R1. The notch amplification can also be seen in picture number 2, where ExpoChirp is set to -46dBV.
I only have a shorted C5 in the connection.
