/technologies/fpga-group/b/blog/posts/learning-xilinx-zynq-a-quadrature-oscillator---variable-frequencyThis post is a follow up on a previous article to generate a quadrature clock for shabaz &#39;s Software Defined Radio (SDR) Experiment Board . It&#39;s a circuit with 4 PWM outputs that are each 90&deg; shifted. I&#39;m adding programmable frequency control. Wit...en-USTelligent Community 12https://community.element14.com/technologies/fpga-group/b/blog/posts/learning-xilinx-zynq-a-quadrature-oscillator---variable-frequencyTue, 31 Aug 2021 21:45:22 GMT93d5dcb4-84c2-446f-b2cb-99731719e767:18a42db6-b481-4d9d-a7d1-519f8faff252shabaz1<p>Hi Jan,</p><p>&nbsp;</p><p>This is looking really neat!</p><p>I was wondering, what will the frequency increment be? Would it need to be more than 8-bit register, to get the resolution finer?</p><p>The resolution likely needs to be at low kHz (like 1-2 kHz max, but preferably less), since it&#39;s possible to do some of the tuning in the SDR receiver software.</p><p>If you&#39;re planning on using it in just one band like say AM broadcast band then that could be a good way to go, if it&#39;s easier to have such resolution there.</p><img src="https://community.element14.com/aggbug?PostID=21917&AppID=19&AppType=Weblog&ContentType=0" width="1" height="1">https://community.element14.com/technologies/fpga-group/b/blog/posts/learning-xilinx-zynq-a-quadrature-oscillator---variable-frequencyTue, 31 Aug 2021 13:16:32 GMT93d5dcb4-84c2-446f-b2cb-99731719e767:18a42db6-b481-4d9d-a7d1-519f8faff252Jan Cumps0<p>This is the Python code that makes the oscillator sweep:</p><p>&nbsp;</p><p><span>[View:/resized-image/__size/1070x296/__key/commentfiles/f7d226abd59f475c9d224a79e3f0ec07-18a42db6-b481-4d9d-a7d1-519f8faff252/contentimage_5F00_216472.png:1070:296]</span></p><p>I changed the fabric clock to 10 MHz because that&#39;s easier to probe than 100 MHz.</p><img src="https://community.element14.com/aggbug?PostID=21917&AppID=19&AppType=Weblog&ContentType=0" width="1" height="1">