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Hantek6074BC-hack to 250MHz
gf:
--- Quote from: rtek1000 on April 28, 2023, 11:19:31 pm ---Some oscilloscope models have 5 ADC of 100MSPS to get 1GSPS, it may be possible to put more HAD1511 in parallel to get a higher sample rate
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Virtually all high speed ADCs use interleaving. Internally, the HMCAD1511 also contains 8 ADC cores @125MSa/s, which can be combined in different ways by on-chip multiplexers. For example, in single-channel mode all 8 cores are interleaved (-> 1GSa/s), and in 4-channel mode two cores are interleaved per channel (-> 250Msa/s per channel).
I am not sure if multiple HMCAD1511 can be interleaved easily to get 2GSa/s or more. Likely it's not impossible, but I guess at higher frequencies, all interleaved cores would be better placed on the same chip. While several low-cost 4-channel 1GSa/s scope models from diffferent manufacturers use the HMCAD1511, the 2-GSa/s scopes seem to use different ADCs.
--- Quote from: rtek1000 on April 28, 2023, 11:19:31 pm ---From what I understand about ADC, 10 samples are needed for each Hz, that is, if all 6xx4 use the same ADC HAD1511 of 1GSPS then you can only get 100MHz of bandwidth.
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The sample rate is whatever it is, and the bandwidth of the frontent is whatever it is. They are not directly related. The sample rate just sets a limit for the highest frequency content of the input signal which can be reconstructed from the samples (almost) exactly with sin(x)/x interpolation. See https://en.wikipedia.org/wiki/Nyquist%E2%80%93Shannon_sampling_theorem
If the bandwidth of the front end is small enough compared to the sampling rate, it may serve as a good enough anti-aliasing filter. OTOH, a frontend with a large bandwidth is rather not supposed to serve as an anti-aliasing filter, and it is up to you to ensure that the input signal is band-limited per se in order not to violate the sampling theorem.
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