I was setting out to look at PSRR in my Rotel 850 sim.
My initial plan was to simply measure the output with various supply rails.
I was then going to move on to automate this as per
LTspice: Using .MEAS and .STEP Commands to Calculate Efficiency | Analog Devices
But I have fallen at the first hurdle. I added a simple .meas directive to the simulation, via the .meas editor.
But I get no result in the log file.
(I also note a LOT of warnings from the model file)
BugBear
My initial plan was to simply measure the output with various supply rails.
I was then going to move on to automate this as per
LTspice: Using .MEAS and .STEP Commands to Calculate Efficiency | Analog Devices
But I have fallen at the first hurdle. I added a simple .meas directive to the simulation, via the .meas editor.
But I get no result in the log file.
(I also note a LOT of warnings from the model file)
BugBear
Attachments
I'm planning to move on to checking what happens when I simulate a real PSU that drops under load (as opposed to a LTSpice voltage source that doesn't), and (finally) what happens to overall THD when there "just happens" to be a high amplitude, low frequency component in the input.
(AKA what happens to the violin sound when the organs kicks in for the finale!?)
BugBear
(AKA what happens to the violin sound when the organs kicks in for the finale!?)
BugBear
Well, I finally managed to set up what I think is an OK test.
I arranged that I could (optionally) inject 1V of ripple onto either the front end OR output driver stages of the Rotel 850, with or without a signal.
The drivers stage has massive PSRR, so I concentrated on the front end (which is where high grade power amplifiers commonly have some exotic smoothing/regulation).
1V of signal looks like this - some harmonic distortion, but waddya' expect from a mid range amp?
(anything below 120dB and above 100kHz is probably an FFT artefact)
BugBear
I arranged that I could (optionally) inject 1V of ripple onto either the front end OR output driver stages of the Rotel 850, with or without a signal.
The drivers stage has massive PSRR, so I concentrated on the front end (which is where high grade power amplifiers commonly have some exotic smoothing/regulation).
1V of signal looks like this - some harmonic distortion, but waddya' expect from a mid range amp?
(anything below 120dB and above 100kHz is probably an FFT artefact)
BugBear
Attachments
- Status
- This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.