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| NorthGuy:
--- Quote from: stj on April 06, 2019, 11:20:30 am ---now 20MHz is kind of worse case - most signals would be 4MHz or less --- End quote --- But if your output is LED, the best you can possibly see is 20 Hz or so. |
| joeqsmith:
--- Quote from: stj on April 06, 2019, 11:20:30 am ---to answer some questions, no mutiplexing, just 30 leds wired direct to the binary>decimal convertor. update rate of the leds would be the rate the data under the probe changes state - that's why the latch is between the dac and binary>decimal decoder. now 20MHz is kind of worse case - most signals would be 4MHz or less - i picked 20 because it's kind of the max you would see a 74ALS series being run. i know they can go higher but it's very rare. --- End quote --- So you want to make something like the following but with a higher BW? |
| stj:
--- Quote from: NorthGuy on April 06, 2019, 12:45:30 pm --- --- Quote from: stj on April 06, 2019, 11:20:30 am ---now 20MHz is kind of worse case - most signals would be 4MHz or less --- End quote --- But if your output is LED, the best you can possibly see is 20 Hz or so. --- End quote --- i can pause the latch on the buffer to hold the sample - or maybe feed it with a 2-3Hz clock |
| stj:
--- Quote from: joeqsmith on April 06, 2019, 12:58:53 pm --- --- Quote from: stj on April 06, 2019, 11:20:30 am ---to answer some questions, no mutiplexing, just 30 leds wired direct to the binary>decimal convertor. update rate of the leds would be the rate the data under the probe changes state - that's why the latch is between the dac and binary>decimal decoder. now 20MHz is kind of worse case - most signals would be 4MHz or less - i picked 20 because it's kind of the max you would see a 74ALS series being run. i know they can go higher but it's very rare. --- End quote --- So you want to make something like the following but with a higher BW? --- End quote --- no, that's a 2D display, i'm after a single row of 30led's your on the right track though, imagine a VU meter with a 20MHz+ frontend. |
| nctnico:
--- Quote from: joeqsmith on April 06, 2019, 12:58:53 pm --- --- Quote from: stj on April 06, 2019, 11:20:30 am ---to answer some questions, no mutiplexing, just 30 leds wired direct to the binary>decimal convertor. update rate of the leds would be the rate the data under the probe changes state - that's why the latch is between the dac and binary>decimal decoder. now 20MHz is kind of worse case - most signals would be 4MHz or less - i picked 20 because it's kind of the max you would see a 74ALS series being run. i know they can go higher but it's very rare. --- End quote --- So you want to make something like the following but with a higher BW? --- End quote --- That is neat. I made exactly the same thing... over 30 years ago. Only mine had a 16 wide * 8 height display. |
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