analog to varied PWM signal

Hello, I would like to develop a circuit that could take a 0-5VDC signal and convert that to a 0-50 hz signal. I would need the ability to adjust the gain and or the pulse width of the output.

Any suggestions?

0 D_Hersey over 10 years ago

They have chips for that, this one goes down to 1Hz. Zero would be a tough gig, thinking about it:
LM331 | Voltage-to-Frequency Converters | Special Function Amplifier | Description & parametrics

Barrie Gilbert, so sexy, so erudite, so good:
http://www.analog.com/static/imported-files/application_notes/511072672AN277.pdf

He invited the Gilbert Cell mixer, among other things, which can be used with a single supply. Found on the front end of most if not all cell phones.
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0 michaelkellett over 10 years ago

The obvious answer is to use a micro - but it would be possible to advise you better if you explained what you are trying to do. A PWM signal wouldn't normally be described as having a variable frequency so your question is a bit puzzling.

MK
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0 D_Hersey over 10 years ago in reply to michaelkellett

One way to make an analog multiplier is to have one operand voltage modulate the frequency of a relaxation oscillator and the other pulse width. Integrating the output yields the product.
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0 D_Hersey over 10 years ago

A uP is indirect and likely glitchy and longer to warm up. The analog chip will yield a smoother output and be easier to implement. This choice is manifested daily in SMPS controllers, and the designers of these chips almost invariably choose the analog solution to this problem.
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0 D_Hersey over 10 years ago

Another rather famous place where multiple params of the signal are simultaneously modulated is QAM. This is the technique that brought modems 'beyond Nyquist' and above the early sluggish baud rates.
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