I'm not seeing anything on the spectrum analyzer for either channel. My circuit is a two stage op amp. My input frequency is a 1kHz sine wave with 200mV peak. I can measure the input and output of the circuit very well with the Oscope for Channel 1 and Channel 2. My gain is about 3.2V/V. Channel 1 is the input and Channel 2 is the output.
Can anyone suggest what I might be doing wrong? The read the instructions on the wiki site for the spectrum analyzer but nothing seemed apparent of what i am doing wrong.
What are your Start/Stop (or Center/Span) settings? Can you post a screenshot, showing these settings?
Same thing with amplitude, you may need to adjust the top/range (and units) to get the best picture of what's going on.
Try setting start to 1Hz, stop to 10kHz, and resolution BW to something near 5Hz. This should allow you to see your fundamental and first few harmonics.
Thanks I tried those settings and it gave me some signals in the frequency domain . Here is the circuit that I built. Its an audio amplifier. I connected it to a 8 ohm speaker through a 220 uF capacitor. Do you know if it's appropriate to look at spectrum analyzer with the actual load connected to the cicruit or just leave it without the load and analyze the frequency components?
One of the uses for a spectrum analyzer is to see whether loading an amplifier causes it to distort. An interesting test would be to test both loaded and unloaded. If connecting the load causes the output to distort, then either reduce the signal amplitude, or use an amplifier with a stronger output stage.