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As know that AD9850 chip module can generate sine waveform, but does it can generate others waveform? as data sheet of AD9850 didnt mention it

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The data sheet shows that the chip includes a comparator, and suggests that it can be used to create a square wave from the (sine wave) DAC output.

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It seems like a round-a-bout way to make a digital signal from a digital signal, but the analog filter should keep the jitter down.

The variable duty cycle @captcha refers to on commercial boards is probably created by comparing the filtered sine wave to a variable voltage.

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The module that is sold on sites like eBay that includes the AD9850 (with crystal, breakout header pins and trimpot) outputs a Sine and a Square wave (at the same time). The trimpot is used to change the duty cycle of the square wave. I built my own Arduino shield with one of these modules and with a bit of code it's reasonably easy to set up. The arduino code is only there to set the frequency. The board outputs both waves.

You may be able to see in the schematic how these boards generate both waves. Sorry I don't have a schematic to provide as I'm not sure if I can post (other people's) schematics freely on this site and I don't have a schematic of the board myself..

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  • \$\begingroup\$ beside square wave, can it generate triangular wave? \$\endgroup\$
    – user37970
    Commented May 26, 2014 at 5:19
  • \$\begingroup\$ Unfortunately it doesn't output a triangle wave. On the datasheet it mentions that it outputs 4 waves: 1) Square Wave comparator’s true output, 2) Square Wave comparator’s complement output 3) Sine Wave Analog Current Output of the DAC, 4) Sine Wave Complementary Analog Output of the DAC. Hope this helps. \$\endgroup\$
    – captcha
    Commented May 27, 2014 at 23:04

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