[time-nuts] RF mixers for oscillator characterization, some questions

Magnus Danielson magnus at rubidium.dyndns.org
Sun Apr 19 23:06:57 UTC 2009

Hej Arnold,

Arnold Tibus skrev:
> Bruce, 
> a very good summary!
> I do not know where I can get the proposed MinCircuits DBM 
> here, I looked to all the big and international well known 
> supplier of electronics parts with negativ result. 
> If I have to import them from USA they could end up even above 
> 100 $ ea. we have in Europe to take the high shipment costs 
> and the 19% VAT into account.  

It was not too hard to find their official list of representatives.
That is what I usually do besides the top catalog firms.

Prices does not seem too bad...

> Is it likely to get used mixers with damaged diodes?
> Did somebody alredy look inside the metal case of the 10514A?

You made me remember I needed too....

>  Will it perhaps possible to reconnect the common ground connections
> such a way that the mentioned loops can be opened?

Yes. The grounds is separated on the PCB, so it is only on the front 
plate that they actually interconnect when the BNCs screw tight.

What's inside then?

Well, there is 4 small torroid cores (as compared to the 10534A which 
has only two cores). It also has 4 diodes (marked as HP 82) and 2 50 Ohm 

The L and R ports have an isolational transformer each, with the 50 Ohm 
resistor loading on the secondary side. A inner transformer then 
follows, with two secondaries, hooked up like expected for a double 
balanced mixer. Essentially this is a double balanced mixer with 
additional isolational transformers and 50 Ohms terminations.

This does not match the datasheet from MiniCircuit for ZP-10514:


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