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Looking for some cheap method of adding a 350uS delay to a pulsed sine wave. It would be useful to emulate a pitch-catch ultrasonic distance measurement setup

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    \$\begingroup\$ You mean like a delay line? \$\endgroup\$ – Ignacio Vazquez-Abrams Jul 24 '15 at 14:41
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    \$\begingroup\$ "COTS solution" means that this is a shopping question, which is off-topic here. \$\endgroup\$ – Dave Tweed Jul 24 '15 at 15:24
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It's a job interview question :) The cheapest available solution is a microcontroller with ADC and DAC. 240kHz is a little fast, but feasible. So you just sample the input signal, store it in the memory, and then put it on output with programmable delay.

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  • \$\begingroup\$ Could use a <$2 MK02FN64VFM10 which has 1.2MSPS 12-bit ADC and 12-bit DAC on-chip 16k x 8 RAM which is sufficient for ~6ms delay at 1.2 MBS without packing, and ~9ms packing 2 x 12 bits into 3 bytes. Of course a bit of code would be required. \$\endgroup\$ – Spehro Pefhany Jul 24 '15 at 19:01
  • \$\begingroup\$ And if I put that together, and costed my company time, it would be around $2000 excluding parts and PCB layout and manufacture. Let's say an even $3000. Hence the question. \$\endgroup\$ – Dirk Bruere Jul 24 '15 at 20:13
  • \$\begingroup\$ @DirkBruere: What Dave Tweed said... \$\endgroup\$ – EM Fields Jul 24 '15 at 20:30
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Run the pulse through about 53cm of distilled water at 25C.

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  • \$\begingroup\$ I already run it through air. I am looking for something to emulate the mechanical bits ie transducers, housing etc. \$\endgroup\$ – Dirk Bruere Jul 24 '15 at 20:14

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