James Hillman wrote:
>I am using a PIC to make a frequency generator 0 to 50,000 Hz with 0.01%
>resolution. I have searched the PICLIST archives and the most suitable IC I
>have come across to do the frequency generation is the ML2036 from Fairchild
>semiconductor. Can anyone suggest anything else ?
>
>Maxim MAX038, Harris HSP45102, Motorola MC145162,Analog Devices AD9850 are
>too expensive and designed for RF so aren't really suitable.
>I have considered using a Direct Digital Synthesis (DDS) algorithm, but
>there is too much else going on in the processor to do this.
>


.01% = 1 part in 10,000. It may be difficult to get such fine
frequency control unless you use DDS.

However, another cheapo analog device to look at is the XR2206,
readily available from jameco.com for ~3.00 USD. I have used it
and prefer it over the 8038 chip, due to less waveform distortion.
You can control it with PIC PWM fed to a BJT stage and get at
least 1,000 different frequencies - although the control curve
will be somewhat non-linear, smaller steps at low end, larger at
high end.

- dan michaels
www.oricomtech.com
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