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Dear all, I am trying to simulate a circuit with negative conductance using transistors and passive components. Does anyone have a circuit for this? Best regards. Sebastian

I would use an AC analysis. Produces a nice plot of frequency response that you can compare to the RIAA curve. That is what I did when I looked at the Carver C1 preamp stage. --

It doesn't seem right to use a pulse signal for an audio application. -- This email has been checked for viruses by AVG antivirus software. www.avg.com

If this is for testing a preamp, it might also depend on whether the preamp has filtering for beyond-audio frequencies, including RFI. Andy

For a 100 Hz square wave, set Tperiod = 10m.? Do you have a calculator?? 1/100 = 0.01 = 10e-3. Then set Ton = Tperiod - (Trise+Tfall)/2. That square wave would generate harmonics extending well past

Not sure what you hope to learn from 20kHz square wave testing of an RIAA preamp, but it would depend on whether the 75μs pole is implemented passively, or in the main feedback loop. Are you testing

I want to know if my Pulse settings are correct. Correct point in not using 20KHz, but something more in the listening range. Like 100Hz to 15KHz Carlos <AI.egrps+io@...> wrote:

Also, I wonder why someone would use a 20 kHz square wave, with anything related to RIAA.? Would you not be better off using a lower frequency, something within the audio band? Andy

Un, what are you asking?? What is an "RIAA square wave"? What is your PULSE waveform intended for?? That should lead you in the direction of answering your own question. We can not read your mind.?

Hi, This should be the first time I will be using a SW to test a RIAA preamp response. I was thinking of copying the settings I use for testing power amps, but I am not sure it's correct. They are:

FYI - I replicated your table() function by copy-and-paste, and it works correctly, as far as I can see. So if a problem remains, it is not in the table() function; it must be something else in your

Because the series of sidebands extend infinitely, a radio receiver will truncate the sidebands that extend beyond its bandwidth. An interesting consequence of this is that the demodulated signal will

Thank you.

See * BF970 PNP model * created using Parts release 6.3a on 09/06/96 at 10:34 * Parts is a MicroSim product. .MODEL BF970 PNP + IS=10.000E-15 + BF=50 + VAF=100 + IKF=10.000E-3 + VAR=100 +

Indeed, if the frequency is always changing, you won't get a clean FFT and interpretation could be challenging.? I suppose you could try the FFT of only one cycle, or as few cycles as possible, to

Since you did not upload a schematic, it is really hard to tell. It is possible that your line with the table is too long.? Did you enter the line (the one starting with B1) as a SPICE Directive

BF970 is an PNP transistor for UHF band (fT=1000 MHz) from Vishay. I visited Vishay site but there was no sign of BF970 (very old). I hope its spice model exists somewhere or of equivalent UHF PNP

The clue was that LTspice always failed to find the initial solution, i.e. the matrix state at time=0, rather than failure mid-way through the analysis, which is what happens in some problems. From

Hello Tony, I hope you're doing well ? Thanks you so much for your help, indeed it works on my side too with "startup" option. How did you find that ? It's almost magic for me :) However, I didn't try

If the frequency constantly changes (so that no cycle of the signal is the same as the cycle before or after), then the FFT will NOT show discrete frequencies. At best it will be difficult to