Sine wave generator

Document created by analog-archivist Employee on Feb 23, 2016
Version 1Show Document
  • View in full screen mode

I'm working on a design of Sine wave generator. The sine shall be in phase with
reference square signal 500Hz. The amplitude shall be controllable. I'm
thinking about use some DDS IC (AD5932).

My question is: Is it possible to control the output amplitude of the sine
signal by this IC? Or do I need to use some controlled amplifier?


It would be nice to know the amplitude range...there are different case

1.Use a part like the AD9838, this part has a pin (FSADJUST) that allows to
control the full scale voltage by controlling the current. There is an AN about
that but generally speaking the span is really small.
2.If you want wide span, the recommendation is :
a.Fixed gain TIA + control full scale voltage
b.Variable GAIN TIA, you can control the amplitude with a digipot for example.

There is a third case, the part has not FSADJUST pin, like the AD5932, use
solution 2b.

You can use a non-inverting amplifier instead of TIA if you don't have negative
supply available for the TIA.