/members-area/personalblogs/b/michael-kellett-s-blog/posts/hp-3325a-synthesizer-function-generatorI recently bought this instrument on Ebay - it&#39;s quite an old design and if you fancy one the 3325B might be a better bet since it has a much more modern processor and a few extra functions (but will cost more). It was first released in 1979, at ...en-USTelligent Community 12https://community.element14.com/members-area/personalblogs/b/michael-kellett-s-blog/posts/hp-3325a-synthesizer-function-generatorTue, 05 Mar 2024 20:18:08 GMT93d5dcb4-84c2-446f-b2cb-99731719e767:8db5ebc9-c67d-45ef-83b3-81a79ad83ab2DAB0<p>Yes, HP used to be the go to brand for these instruments.</p> <p>They always had the best quality.</p> <p>Great find.</p><img src="https://community.element14.com/aggbug?PostID=27730&AppID=323&AppType=Weblog&ContentType=0" width="1" height="1">https://community.element14.com/members-area/personalblogs/b/michael-kellett-s-blog/posts/hp-3325a-synthesizer-function-generatorMon, 04 Mar 2024 02:03:30 GMT93d5dcb4-84c2-446f-b2cb-99731719e767:8db5ebc9-c67d-45ef-83b3-81a79ad83ab2shabaz1<p>Wow, nice instrument! (and the frequency counter!). Really neat that it has such extremely high granularity. And also supports log sweep.<br />I just took a peek at the service manual. I might steal a bit of the reference input circuit.</p> <p><img alt=" " height="275" src="/resized-image/__size/1962x550/__key/commentfiles/f7d226abd59f475c9d224a79e3f0ec07-8db5ebc9-c67d-45ef-83b3-81a79ad83ab2/ref_2D00_input_2D00_hp.jpg" width="980" /></p> <p>I want to build a freq synthesizer (discussed not in the blog, but in the comments here:&nbsp;&nbsp;[mention:01df3eeebd2442ef9257cbcbeac95f97:f7d226abd59f475c9d224a79e3f0ec07]&nbsp;&nbsp;) and I don&#39;t have a 10 MHz external reference yet. The circuit I was going to use:</p> <p><img alt=" " height="269" src="/resized-image/__size/808x538/__key/commentfiles/f7d226abd59f475c9d224a79e3f0ec07-8db5ebc9-c67d-45ef-83b3-81a79ad83ab2/ref_2D00_input_2D00_initial_2D00_idea.jpg" width="403" /></p><img src="https://community.element14.com/aggbug?PostID=27730&AppID=323&AppType=Weblog&ContentType=0" width="1" height="1">https://community.element14.com/members-area/personalblogs/b/michael-kellett-s-blog/posts/hp-3325a-synthesizer-function-generatorSun, 03 Mar 2024 19:03:07 GMT93d5dcb4-84c2-446f-b2cb-99731719e767:8db5ebc9-c67d-45ef-83b3-81a79ad83ab2dougw0<p>What is the max frequency?</p><img src="https://community.element14.com/aggbug?PostID=27730&AppID=323&AppType=Weblog&ContentType=0" width="1" height="1">https://community.element14.com/members-area/personalblogs/b/michael-kellett-s-blog/posts/hp-3325a-synthesizer-function-generatorSun, 03 Mar 2024 17:10:54 GMT93d5dcb4-84c2-446f-b2cb-99731719e767:8db5ebc9-c67d-45ef-83b3-81a79ad83ab2genebren0<p>Not a bad buy!</p><img src="https://community.element14.com/aggbug?PostID=27730&AppID=323&AppType=Weblog&ContentType=0" width="1" height="1">