How to use DA to adjust VCO to generate 900K ~ 1500KHz freq?

[wwwrabbit]

use of 74ls624

I want to design a frequency generator to produce around between 1000KHz and 1024KHz signal. If I use two crystals, it's a choice. but I want to use VCO to do this. as I have a spare DA on my MCU, I want to use this to adjust VCO to generate Frequcy range 900K ~ 1500Khz. Could you guys give me some advice? Thank you inadvance.

 

[atmaca]

frequency generator 1000khz

search google you will find lots of circut topology on VCOs

 

[IanP]

Re: frequency generator

As VCOs I would use NE564
**broken link removed**
**broken link removed**
or 74LS624
**broken link removed**

Although they may be from old ages (atiques in fact) but they are very easy to use ..

What frequecy steps would you like to have? 1kHz, 100Hz, ..