[ARC5] HF Converter - feeding mixer with a square wave?

[1oldlens1]

You have another person confused.  My understanding has always been that a mixer was fed with signals of two different frequencies and put out both frequencies plus the sum and difference frequencies.  My understanding so is this requires the circuit to be non-linear.  If not why does a straight piece of wire do this?  I am away from Home and can't look at my books.Note that a mixer and an amplitude modulator behave in much the same way. What am I missing? Sent from my Galaxy
-------- Original message --------From: Mike Feher <n4fs at eozinc.com> Date: 3/17/22  7:18 PM  (GMT-08:00) To: 'Bob kb8tq' <kb8tq at n1k.org> Cc: 'ARC-5' <ARC5 at mailman.qth.net> Subject: Re: [ARC5] HF Converter - feeding mixer with a square wave? The most ideal mixer is a multiplier. And it is linear. The math has not changed in hundreds of years except maybe for the case of zero divided by zero. When I was young, I wanted to be a professor and tutored my classmates many math and EE courses. Always got frustrated when what was obvious to me, I could not make a few of them understand. So, I turned out to be just an EE who put in 50 years working for the DOD one way or the other. This will be my last post on the subject as there have been way too many already. Obviously, Tom has a lot more patience than I, and I hope you try to understand what he is telling you. 73 – Mike   Mike B. Feher, N4FS89 Arnold Blvd.Howell NJ 07731848-245-9115 From: Bob kb8tq <kb8tq at n1k.org> Sent: Thursday, March 17, 2022 9:40 PMTo: Mike Feher <n4fs at eozinc.com>Cc: Tom Lee <tomlee at ee.stanford.edu>; ARC-5 <ARC5 at mailman.qth.net>Subject: Re: [ARC5] HF Converter - feeding mixer with a square wave? Hi Oddly enough pretty much everything we used was in the form of notesfrom the prof. The explanation was that the last time they had done “ a course like this” was back in the early 1950’s. At the point I was there (the 1970’s) the textbook world had not caught up. BobOn Mar 17, 2022, at 9:16 PM, Mike Feher <n4fs at eozinc.com> wrote: Bob –  Can you reference the book that you used during your studies? 73 – Mike  Mike B. Feher, N4FS89 Arnold Blvd.Howell NJ 07731848-245-9115 -----Original Message-----From: arc5-bounces at mailman.qth.net <arc5-bounces at mailman.qth.net> On Behalf Of Bob kb8tqSent: Thursday, March 17, 2022 9:12 PMTo: Tom Lee <tomlee at ee.stanford.edu>Cc: ARC-5 <ARC5 at mailman.qth.net>Subject: Re: [ARC5] HF Converter - feeding mixer with a square wave? Hi At least when I took the course in school on this stuff, the basic definition of “linear” was indeed that the output was the input times a constant. Anything other than that was “non-linear”. This is at the root of the conversation about mixers being non-linear. If that *is* you definition of linear then mixers must be non-linear. Bob > On Mar 17, 2022, at 9:09 PM, Tom Lee <tomlee at ee.stanford.edu> wrote:> > Think about how one actualy uses a multiplier as a mixer, Bob. The input-output relationship of relevance is that between the IF output and the RF input. That is supposed to be linear, right? That is, the output should be a constant times the input, just as you yourself stated as the requirement.> > --Tom> > --> Prof. Thomas H. Lee> Allen Ctr., Rm. 205> 350 Jane Stanford Way> Stanford University> Stanford, CA 94305-4070> http://www-smirc.stanford.edu> > On 3/17/2022 17:45, Bob kb8tq wrote:>> Hi>> >> If you accept the definition that a “linear” circuit *only* produces >> the input times some constant ( = the gain ) then anything that >> multiplies must be non-linear.>> >> If you look at a different definition, then of course, they can be linear.>> It’s just a mater of what your base definitions are.>> >> Bob>> >>> On Mar 17, 2022, at 8:13 PM, Tom Lee <tomlee at ee.stanford.edu> wrote:>>> >>> (Just to clarify, this was posted in response to Bob Nickels, not to >>> Mike St. Angelo -- sorry for the confusion, Mike!)>>> >>> --Tom>>> >>> -->>> Prof. Thomas H. Lee>>> Allen Ctr., Rm. 205>>> 350 Jane Stanford Way>>> Stanford University>>> Stanford, CA 94305-4070>>> http://www-smirc.stanford.edu>>> >>> On 3/17/2022 12:16, Tom Lee wrote:>>>> I wish people would stop repeating the claim that mixers are inherently nonlinear. That’s completely false. It is true that nonlinear things can produce mixing, but that’s a side effect, not an inherent property!>>>> >>>> Good mixers have to be linear. You want the IF output to be proportional to the RF input.>>>> >>>> We treat mixer nonlinearity in much the same way as we treat amplifier nonlinearity. It is an undesirable property and considerable effort is expended to minimize it.>>>> >>>> Tom>>>> >>>> Sent from my iThing; please forgive the typos and brevity>>>> >>>>> On Mar 17, 2022, at 11:39, MICHAEL ST ANGELO <mstangelo at comcast.net> wrote:>>>>> >>>>> Bob,>>>>> >>>>> Enjoyed that article and the one about the Si5351 Quadrature oscillator. Have the tried feeding the Si5351 to the SA612 instead of an Epson? It gives the the ability of easily changing frequency.>>>>> >>>>> The SA612 and Si5351, what a pair for experimenters.>>>>> >>>>> Mike N2MS>>>>> >>>>>> On 03/17/2022 1:05 PM Robert Nickels <ranickels at gmail.com> wrote:>>>>>> >>>>>> >>>>>>> On 3/17/2022 11:10 AM, Phillip Carpenter wrote:>>>>>>> Can you please share the circuit diagram of your universal converter board that you used with the BC-453 receiver?>>>>>> I've added an article about it to my website: >>>>>> https://tinyurl.com/mrj7rndd>>>>>> >>>>>> The 4.7uH/100pF values shown work for 40 meters, or calculate >>>>>> your own - I use a 10uH fixed inductor and 150-180pf capacitor for 75-80 meters.>>>>>> >>>>>> 73, Bob W9RAN>>>>>> >>>>> ______________________________________________________________>>>>> ARC5 mailing list>>>>> Home: http://mailman.qth.net/mailman/listinfo/arc5>>>>> Help: http://mailman.qth.net/mmfaq.htm>>>>> Post: mailto:ARC5 at mailman.qth.net>>>>> >>>>> This list hosted by: http://www.qsl.net Please help support this >>>>> email list: https://www.qsl.net/donate.html>>> ______________________________________________________________>>> ARC5 mailing list>>> Home: http://mailman.qth.net/mailman/listinfo/arc5>>> Help: http://mailman.qth.net/mmfaq.htm>>> Post: mailto:ARC5 at mailman.qth.net>>> >>> This list hosted by: http://www.qsl.net Please help support this >>> email list: https://www.qsl.net/donate.html>  ______________________________________________________________ARC5 mailing listHome: http://mailman.qth.net/mailman/listinfo/arc5Help: http://mailman.qth.net/mmfaq.htmPost: mailto:ARC5 at mailman.qth.net This list hosted by: http://www.qsl.netPlease help support this email list: https://www.qsl.net/donate.html 
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