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simoninns / DomesdayDuplicator

High-speed LaserDisc RF sampler
GNU General Public License v3.0
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Dual channel ADC for VHS tape capture #84

Open simoninns opened 5 years ago

simoninns commented 5 years ago

For use with VHS tape systems (and other capture scenarios where there are dual sources of analogue data), it would be useful for the duplicator board to provide 2 synchronised channels of ADC running from the same sample clock.

This would need some testing though as it's not clear if the USB3 can sustain 2 40MSPS streams (testing so far has been up to 75MSPS).

happycube commented 5 years ago

VHS doesn't need anywhere near 40msps to work effectively, so there's definitely enough bandwidth there.

simoninns commented 5 years ago

Good point - since the ADC filter is fixed, the FPGA could be used to decimate the sample in software (to lower the sample rate without changing the ADC clock) - which would then keep the design more universal.

harrypm commented 10 months ago

Just thought I would add a footnote

Mimimum Resampled:

Mimium Recommended:

While mimium sampling is great for post space saving oversamping for VHS is plus in the event of dropouts or out of spec signals.

Video8 / Hi8 fall into 28msps safe relm and are 1 RF tap capture formats.

harrypm commented 6 months ago

Just going to note the new adc_usb3 / SMIRF (Now called the MISRC), its in a very dev board work in progress state and software/audio boards are a work in progress aswell, but it has great potential.

Cost: 150 Euro +- 25 Euro - JLCPCB/PCBway direct fabrication

PCB: 20-30USD / Parts 50-70USD

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