[time-nuts] Close in phase noise of microwave VCOs

Jim Lux jimlux at earthlink.net
Sat Jun 20 09:25:42 EDT 2015


On 6/19/15 9:30 PM, Bob Camp wrote:
> Hi
>
> One of the most interesting things about the last paper mentioned:
>> On Jun 19, 2015, at 8:57 PM, Charles Steinmetz <csteinmetz at yandex.com> wrote:
>>
>> Rick wrote:
>>
>>> However, a better tutorial would be the one written by
>>> HP's Dieter Scherer which was published in Microwaves
>>> & RF Magazine (or possibly Microwave Journal).  I believe
>>> the same content was available from HP as an Ap Note or
>>> something.
>>
>> I suspect the paper you are referring to is:
>>
>> Design Principles and Test Methods for Low Phase Noise RF and Microwave Sources (Scherer, 1978)
>>
>> It is available on Didier's site at:
>>
>> <http://www.ko4bb.com/manuals/download.php?file=03_App_Notes_-_Proceedings/Scherer_Low_noise_source_design_and_test.pdf>
>>
>> There are two other Scherer papers there:
>>
>> Generation of Low Phase Noise Microwave Signals (Scherer, 1981)
>> <http://www.ko4bb.com/manuals/download.php?file=03_App_Notes_-_Proceedings/Scherer_Low_PN_Signal_Generation.pdf>
>>
>> The "Art" of Phase Noise Measurement (Scherer, 1985)
>> <http://www.ko4bb.com/manuals/download.php?file=03_App_Notes_-_Proceedings/Scherer_Art_of_PN_measurement.pdf>
>>
> ^^^^^^^^^ this one
>
>> Best regards,
>>
>> Charles
>>
>
> is that it has a phase noise plot on an open loop microwave source down to 10 Hz. Not quite the VCO Jim
> was looking for, but close ….
>
>

page 25 shows down to 100 Hz, "Typical Free-Running Source at 10 GHz". 
Eyeballing it it looks like 20dB/decade from 10-100k, a bit more from 
1-10k, and almost 30 dB/decade from 100Hz to 1k. I wonder what the 
source was?

The SAW is definitely in the 30dB/decade bucket


This makes a good case for the "30dB/decade very close in"






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