Hello,
On the 11729C, part of the old 3048A phase noise analyzer, it was possible to configure the internal SAW 640 Mhz filter to oscillate with a 11729-60096 "cable attenuator". Of course it acts as a 180° phase shifter but what is the value of the attenuator and eventually the total mechanical lenght to shorten the try and cut method ? Thank you.
Hi jfphp!
The instrument you are describing is the 11729C Carrier Noise Test Set, and it is an obsolete item. Its page is below:
The closest operation manual for it is found on the "Document Library" tab, titled "11729C Carrier Noise Test Set Operating and Service Manual".
On page 1-0, I found a reference to the "Cable and Attenuator", which is described as being "used to configure the internal 640 MHz oscillator".
Upon further reading, there are two ways of using the Carrier Noise Test set to make phase noise measurements, Phase Detector Method and Frequency Discriminator Method. On page 1-2, there's a good chart that describes the discrete use cases, with details such as if you need a drive signal and the frequency range:
In your case, if you have the Cable Assembly, you can directly connect it to the analyzer to do either of these measurements, there's no need to change the length.
If you do not have the cable, you cannot emulate this method, as the value of the attenuator is proprietary information. However, you can use an external RF source. The document suggests an HP 8662A Synthesized Signal Generator but the specs only require the frequency to go between 5 MHz and 1280 MHz, like the chart above suggests. Since this is an obsolete product as well, you can use any new signal generator with these specifications. The additional benefit of using a signal generator is that you will also not degrade the absolute system noise floor when you're close in to the carrier.
Hope this helps!
Bertie
Hi jfphp!
The instrument you are describing is the 11729C Carrier Noise Test Set, and it is an obsolete item. Its page is below:
http://www.keysight.com/en/pd-11729C%3Aepsg%3Apro-pn-11729C/carrier-noise-test-set-5-mhz-to-18-ghz?pm=PL&nid=-536900197.536895853&cc=US&lc=eng
The closest operation manual for it is found on the "Document Library" tab, titled "11729C Carrier Noise Test Set Operating and Service Manual".
On page 1-0, I found a reference to the "Cable and Attenuator", which is described as being "used to configure the internal 640 MHz oscillator".
Upon further reading, there are two ways of using the Carrier Noise Test set to make phase noise measurements, Phase Detector Method and Frequency Discriminator Method. On page 1-2, there's a good chart that describes the discrete use cases, with details such as if you need a drive signal and the frequency range:
In your case, if you have the Cable Assembly, you can directly connect it to the analyzer to do either of these measurements, there's no need to change the length.
If you do not have the cable, you cannot emulate this method, as the value of the attenuator is proprietary information. However, you can use an external RF source. The document suggests an HP 8662A Synthesized Signal Generator but the specs only require the frequency to go between 5 MHz and 1280 MHz, like the chart above suggests. Since this is an obsolete product as well, you can use any new signal generator with these specifications. The additional benefit of using a signal generator is that you will also not degrade the absolute system noise floor when you're close in to the carrier.
Hope this helps!
Bertie