DAC for Sqare Wave Signal

V

VictorK

New member
Hello together,
I am trying to generate a Signal, that consists of a sqare wave with variing Amplitude.
The edges should be quite sharp. I saw some steps, while switching from low to high on a PT8211 with my signal. Could you suggest me a good i2s DAC without an output filter that would let the signal look more digital? Or do I have to deactivate some output filters in the Teensy Audio library?

As far as I understand, most audio DAC's have output filters, that will change the sharpness of my signal.


Thank you very much,
Victor
 
May be a combination of "non-audio" DAC (on I2C or SPI) for the amplitude signal, and digital output. All connected to an op-amp.
Or a DAC to drive a variable gain amplifier.
 
I've yet to find a DAC using i2S that's not related to audio. Hence, always need a way around the filters.
Best to use SPI or i2C DAC not related to audio, like MCP48xx or MCP49xx series. MCP4922 is pretty popular.

An alternative is to use a digital pot controlled by i2C or SPI.
https://www.digikey.ca/en/products/...DaICYEsDmCAuBDANgAgA4HtUBTAO1QXwFsjiAnEAXQF8g
Pick the resistance, resolution, linear vs log taper. Send a digital output GPIO pin into the pot. Some of these pot have memory to save a setting. Keep in mind, they have a slow (dozens of micro-seconds) in response time.
 
BillFM said:
I've yet to find a DAC using i2S that's not related to audio.
Click to expand...

Probably because I2S stands for Inter-IC-Sound? They pretty much are all sigma-delta and pipelined, so fixed crystal-locked sample rate and filtering and decimation is integral to how they function.
 
You might consider using multiplying DAC. Such DAC has digital input and analog input. The analog input is multiplied by the result od digital to analog conversion. If you drive analog input of such DAC from Teensy digital output you would be able to generate non-bandlimited square wave with amplitude controlled by DAC
 
You might consider using multiplying DAC. Such DAC has digital input and analog input. The analog input is multiplied by the result od digital to analog conversion. If you drive analog input of such DAC from Teensy digital output you would be able to generate non-bandlimited square wave with amplitude controlled by DAC. There are Multiplying DACs with bandwidth in megahertz range so you will get sharp edges.
 
Wow. THank you very much for the replies. That already gave me enough input to get closer to a solution.
Thank you very much!
 
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