Re: [LTSPICE] mixer needed

"colin" <no.spam.for.me@xxxxxxxxxxxx> schrieb im Newsbeitrag
news:i4Xse.23556$m4.16585@xxxxxxxxxxxxxxxxxxxxxxx
> "colin" <no.spam.for.me@xxxxxxxxxxxx> wrote in message
> news:XxTse.22599$m4.9316@xxxxxxxxxxxxxxxxxxxxxxx
>> Hi,
>> is there a mixer availble in LTSPICE?
>>
>> just a simple idealised (double balanced) one would do ..
>>
>> ive used the modulator before but this can only modulate a fixed singal
>> frequency
>> i need to mix 2 multi frequency signals.
>>
>
> ok my next problem is i need to introduce a sinusoidaly varying time delay
> into a signal, i cant think what i can use to do this, in the real world
> it
> is the result of varying transmision distance wich is what i wish to
> examine
> the effects of .. any ideas ? i cant use the sffm as it is not a single
> frequency.
>
> Colin =^.^=

Hello Colin,

No problem. The B-source can do it. The variable "time" is available
in the behavioral sources(B).

V=sin(2*pi*f0*(time+deltaTime*sin(2*pi*fdelta*time)))

With numbers:

V=sin(2*pi*1k*(time+0.1m*sin(2*pi*10*time)))

This is a 1kHz sine waveform with a varying delay of +/- 0.1ms and
a frequency of 10Hz.

Increase your time window for the FFT to multiples of 0.1 seconds
in this case. You should also rise the number of samples in
the FFT to 131072. The spectrum looks like PM.

Best regards,
Helmut


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