PWM questions

[Frozen01]

Hello all.

I am looking for some guidance here for now and then maybe more detailed infomation later.

I am looking to generate an AM modulated signal using PWM, if it is even possible. My maximum carrier frequency is in the 2MHz range with the minimum in the 200KHz range. The modulating signal will be around 1000Hz. Is this even possible with a PIC and CCS C??

Thanks!

[ttelmah]

Probably, no.
It'd depend on unspecified factors:

1) How many modulation 'levels' you need?.
2) What step size is acceptable in the frequency?.

If (for instance), you wanted a minimum of 32 different widths at 2MHz, then your master clock, would need to be at least 64MHz. Beyond most PICs. Worse though, if you had the same 64MHz source, and wanted to generate a frequency of 1.8MHz, the 'nearest'you could do, would be 64/36 = 1.7777MHz.

Realistically, use a chip designed for the job, and control this with a PIC. There are programmable tone generators easily available, and some offer analog modulation as well.

Best Wishes

[Frozen01]

Thanks for the reply... Can you point me to a source where these calculations came from.