I have been doing some evaluations of Linsim and I have identified a couple of minor issues.?
In my early tests, I selected 1 path and a spread of 1Hz and and AWGN with SNR=25dB.?
I did one set of tests at a sample rate of 8kbs and another set at 48kbs. I repeated the tests?
with path 1 selected, a spread of 1Hz, and an offset of +5Hz.?

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I am using Windows 11+Dell G10 laptop.

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Observations

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1. I intercomapared Linsim v2.0.4 and and Moe Wheatley's Pathsim v1.0. I generated a 1kHz sinewave
with a 60 sec duration at a sample rate of 8kbs. In this case the time domain wave forms exhibited
very similar envelope fluctuations. When I performed an FFT on the records the resulting spectra
exhibited a Gaussian shape with the same width. When I applied an offset of +5.0Hz, the spectrum
shifted up by 5.0Hz with Pathsim. With Linsim, the Gaussian spectrum shifted down by -5.0 Hz. So there?
is a potential sign error with the offset in the Linsim code.

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2. I performed an additional set of tests with a 1kHz sinewave with a 60sec duration and a sample
rate of 48kbs. In this case I did not use Pathsim since it only works with a sample rate of 8kbs.
I first applied the 1kHz sinewave to Linsim with Path 1 selected, a spread of 1 Hz, and 0 offset.
The resulting output waveform exhibited much faster envelope fluctuations. This was confirmed?
with the FFT, which showed markedly wider Gaussian spectrum-the width increased approximately 6x.

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3. I suspected that this spread issue has something to do with the different data rates since is 6x
larger than the 8kbs case. I then repeated the test with a spread of 1/6 = 0.166, that?
corresponds to the ratio of the data rates 8kbs/48kbs. The resulting spectrum using an FFT showed?
the correct shape and frequency spread.

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4. I think this spreading issue can be corrected in Linsim by applying a scale factor to the
?spread that accounts for the ratio: 8kbs/(the selected date rate kbs)--My best guess :-)
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5. When I applied a +5.0 Hz offset with the 48kbs sinewave the resulting spectrum shifted down
-5.0 Hz. So this Offset sign error is the same at the higher sample rates.?

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Summary

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1. Linsim is a robust and much needed update to Pathsim that enables processing of .wav files?
for a variety of data rates in the range 8kbs to 48 kbs.

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2. When using Linsim at data rates other than 8kbs, adjust the spread using a scale factor of
8kbs/(the selected data rate kbs).

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3. There is a sign error in the offset. So simply switch the sign of the desired frequency offset.

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4. I have applied pulse trains generated with Matlab to Linsim and I will report on my findings?
soon.

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Bob Johnk, WB0VGD?

Arvada, Colorado