开云体育

Just to clarify-
The 3575 is broadband and requires no special source -or any other LOs - just a test frequency source that covers the range of interest-obviously a swept source would be more useful but not essential.


The 3570, OTOH, does require a particular combination of sources and LOs- it is a heterodyne instrument-as opposed to the broadband 3575 - and while it shares the same basic input frequency range (0 - 13MHz) it requires a fixed LO at 20 MHz (from memory) and a swept LO source that covers 20-33 MHz.
These LO frequencies, as well as the test frequency source, (0-13MHz) are all produced from the 3330B, which is a magnificent instrument, very underrated these days but still very competitive for what it does.

The 3570 is a dual channel instrument that can measure relative amplitude and phase between its channels with remarkable resolution-it is available in 50 and 75 ohm versions but I believe the impedance conversion is fairly straight forward (75 to 50 for example)
Be aware there is a 3571 out there which is a later 'version' of the 3570 and looks to a first glance to be identical, but it does NOT allow phase measurements, only relative amplitude.

DaveB, NZ