Rene Wolf - VHS-decode vs Signal degradation - Nov 2023

The cool thing you can do with full RF captures is taking advantage of any SDR or Audio Processing tools on the market for inspecting the waveforms.

Import -> RAW Data

Byte Order -> Little Eiden

Sample Rate ->

4000000 DdD 40MHz/16-bit

2860000 cxadc 28.6 MHz/8-bit

3580000 cxadc3 35.8 MHz/8-bit

1430000 10cxadc 14.3 MHz/16-bit

1790000 10cxadc3 17.9 MHz/16-bit

View -> Show Spectral Frequency Display (Shift+D)

Then you can use normal visual inspection to determine if it's signal is too low or too high.

It's recommended to use 8/16bit FLAC compressed or uncompressed 8/16bit captures for this task and set your cache directory to a location with enough space or you will possibly zero-fill a drive.

Right-click on the left-hand side to change settings and enable the spectrograph.

You can change the settings according to the sample rate used for the capture.

ld-analyse allows you to view the values of your .json metadata file with visually assisted graphing.

Black SNR (Signal To Noise Ratio) is your basic quality indicator.

40-50 dB - Great Signal

30-40 dB - Good Signal

20-30 dB - Weak Signal

10-20 dB - Poor Signal