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How to drive level 7 diode ring mixer LO?

时间:04-04 整理:3721RD 点击:
I?m attempting to design and build an upconverter that will mix LF (100-150 khz) signals with a 312.5 Mhz local oscillator and transmit the signal a short distance to a receiver. I have decided to use the ADE-1 mixer from mini circuits which is a level 7 mixer, requiring 7dbm to adequately bias the internal diodes. My question is about what type of oscillator/driver I can use to provide this.

I have found a few possibilities for creating the clock signal such as this integrated PLL/VCO or one of these oscillators but I'm not sure how to amplify the output of these to drive the ADE-1.

An additional complication is that all of the options I have found to generate the LO output a differential signal (LVPECL, LVDS) and the ADE-1 seems to expect a single ended signal. Would something like this MAX2471 suffice? It can convert from differential to single ended and provide 14db of power gain.

I appreciate any insight that people may have on this. Thanks!

CDCM61001 and other oscillators are compatible with digital circuits so I'm not sure that they can drive 50 Ohm impedance.( maybe lower)
All you have to do is to find/design a proper sinusoidal oscillator and conventional PLL.
Or, you can also design your VCO and find a proper PLL.

Thanks for your help with this. I think I understand what you’re saying but I don’t have much experience with PLLs, can you clarify what you mean by ‘conventional’. If I was to build a Colpitts oscillator for 312.5 MHz, what type of PLL would be appropriate to stabilize it?

As an aside, I'm trying to find resources to learn more about techniques for building analog oscillators at these higher frequencies but I'm having a hard time, everything I find is targeted for digital systems. Any pointers to good study material would be greatly appreciated!

Parts like the ADE-1 are specified with a sinusoidal LO from a 50ohm source, like what you would get from an RFIC. I would expect degraded performance if you drive it directly through a digital output. But if you add some resistance to make the output look like 50ohms, and filter off the harmonics, it should work fine.

ADE-1 cannot be used as an upconverter in your situation, because the RF input frequency range of the mixer is 500kHz to 500MHz, and you need the RF input to go down to 100kHz.
Some of the diode mixers are bidirectional, allow swapping the RF and IF ports, but you have to try it.

https://ww2.minicircuits.com/pdfs/ADE-1.pdf

Thanks for the advice, I like your idea about filtering the harmonics out of the digital clock however I think I’ll use this as an excuse to learn how to design a proper analog PLL oscillator. I’m on the hunt for a good book or online resources.


You are absolutely right about the limitations of the RF port, I’m planning on swapping the RF/IF ports as you suggest. The SV1AFN upconverter uses the ADE-1 successfully in this configuration to get great results in the very low frequency band.

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