Mixer Circuit Help

excetara2 · 26th February 2008, 07:40 PM

I have a simple RF section where I am trying to mix a 100Khz and a variable signal. Ranging around 98-102Khz. I need to build a mixer to get the difference of these frequencies. I wasn't sure what would be the best design or what to use? I was thinking about using Fets. I am new to this game so don't know a lot. The output will be fed to a low-pass filter to get rid of the addition of the two signals. I couldn't find any simple designs on the boards. Any help would be great.

Lsharptec1 · 26th February 2008, 08:03 PM

Excetara2,

You might try posting your question on this forum:

electro-tech-online.com

Those guys are heavy into circuitry.

Larry

MaxS · 26th February 2008, 08:18 PM

Hello

For mixing, you have to use a multiplier. By example, those kind of device works well :
http://www.analog.com/en/subCat/0,28...0%255F,00.html

Some explanations here :
http://en.wikipedia.org/wiki/Frequency_mixer

http://www.electronics.dit.ie/staff/...ultipliers.pdf

Some interestings readings can be found with your favorite search engine.

unclejed613 · 26th February 2008, 11:58 PM

super simple answer: diode ring mixer. 4 schottky diodes and two easy to make toroid transformers. unit has 2 input ports and 1 output port. output port contains sum and difference frequencies, and a simple filter lets you select sum or difference. also known as a double balanced mixer.

a bipolar transistor or jfet would give you a mixer with gain, but requires a bit more finesse to design properly. the diode ring is a wideband design, the transistor mixer usually requires tuned circuits at the inputs and output.

excetara2 · 27th February 2008, 01:32 AM

Four shockty diodes in a ring. Can you draw a simple schematic of what this would look like?

26th February 2008, 07:40 PM	#1
excetara2 diyAudio Member Join Date: Jun 2006	Mixer Circuit Help I have a simple RF section where I am trying to mix a 100Khz and a variable signal. Ranging around 98-102Khz. I need to build a mixer to get the difference of these frequencies. I wasn't sure what would be the best design or what to use? I was thinking about using Fets. I am new to this game so don't know a lot. The output will be fed to a low-pass filter to get rid of the addition of the two signals. I couldn't find any simple designs on the boards. Any help would be great.

26th February 2008, 08:18 PM	#3
MaxS diyAudio Member Join Date: Mar 2006 Location: France	Hello For mixing, you have to use a multiplier. By example, those kind of device works well : http://www.analog.com/en/subCat/0,28...0%255F,00.html Some explanations here : http://en.wikipedia.org/wiki/Frequency_mixer http://www.electronics.dit.ie/staff/...ultipliers.pdf Some interestings readings can be found with your favorite search engine. __________________ Ca marche pas ! Tu ne l' as pas branché non plus ....

26th February 2008, 11:58 PM	#4
unclejed613 diyAudio Member Join Date: Dec 2006	super simple answer: diode ring mixer. 4 schottky diodes and two easy to make toroid transformers. unit has 2 input ports and 1 output port. output port contains sum and difference frequencies, and a simple filter lets you select sum or difference. also known as a double balanced mixer. a bipolar transistor or jfet would give you a mixer with gain, but requires a bit more finesse to design properly. the diode ring is a wideband design, the transistor mixer usually requires tuned circuits at the inputs and output. __________________ Vintage Audio and Pro-Audio repair ampz(removethis)@sohonet.net spammer trap: http://www1284177414881.v-dc.net/

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26th February 2008, 08:03 PM	#2
Lsharptec1 diyAudio Member Join Date: Oct 2004	Excetara2, You might try posting your question on this forum: electro-tech-online.com Those guys are heavy into circuitry. Larry

27th February 2008, 01:32 AM	#5
excetara2 diyAudio Member Join Date: Jun 2006	Four shockty diodes in a ring. Can you draw a simple schematic of what this would look like?

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