[time-nuts] 35601A as stand-in for 11848A ?

[Bruce Griffiths]

Bruce Griffiths wrote:
> SAIDJACK at aol.com wrote:
>   
>> Hi Bruce,
>>  
>> I am pretty sure the Mixers' DC output is near zero when I am in lock,  since 
>> it only needs to compensate for the Opamps' offset voltage (very  small).
>>  
>> While the PLL is working on lock, the Mixer is slowly "homing-in"  on the 
>> lock voltage, and I don't really see that affecting the noise floor at  all (the 
>> PLL loop bandwidth is about 1/2Hz, and thus below the analyzers' cut  off, so 
>> I am actually seeing measurements before the PLL is fully locked  already).
>>  
>> Something else is a bit awry here...
>>  
>> bye,
>> Said
>>   
>>     
>
>   
Said

An even simpler mixer output noise test is to just drive the LO port,
the output noise should be lower than when the RF port is also driven
but should nevertheless serve as a useful indicator of mixer health.

Bruce