Square Wave to Sine Wave

[DPJ]

Hi
Can any One Help
I need to convert a varable Square Wave Between 25Khz to 100Khz to a varable sine wave and if possible keeping constant amplitude
any help would be appriciated.

 

[nbucska]

There are several ways depending requirements:

1.) CMOS buffer ( for constant amplitude ) followed by multipole lowpass filter.
2.) Multiply frequency e.g. by 256 using phase lock loop
-- ROM sine wave look-up table -- DAC . If multiplier is low, follow by low pass filter.
3.) Use MC1648 VCO in PLL -- it has AGC.

If need more help send specs to nbucska@pcperipherals.com
Good luck Nick