HP 8753E manual Pical Test Setup

Frequency Offset Menu

If you press [=I ~~~~~~~~~~’ ~~~~~~~~~,“‘~~~ , the andyzer flows phase-locked

operation with a frequency offset between the internal source and receiver. This feature is used in swept RF mixer measurements and has an upper frequency limit equal to that of the analyzer being used.

This feature allows you to set the RF source to a tied offset frequency above or below the receiver (as required in a mixer test, using a swept RF/IF and fixed LO). Then you can input a signal to a device over one frequency range and view its response over a different frequency range. The maximum delay between the RF source and the R input is 0.3 microseconds. The analyzer will show a signal that is a composite of the desired RF signal, image response, and spurious signals,

You can use the frequency offset in any sweep type in network analyzer mode. The two user-defined variables in this mode are receiver frequency and offset frequency (LC). The analyzer automatically sets the source frequency equal to IF + Lo or IF - Lo.

Mixer measurements and frequency offset mode applications are explained in application note 8753-2, “RF Component Measurements Mixer Measurements using the HP 8753B Network Analyzer,” HP part number 5956-4362. This application note was written for the HP 8753B but also applies to the HP 8753E. Also see product note 8753-2A, HP part number 5952-2771.

Primary Applications

Frequency offset mode is useful for the following types of measurements on frequency- translating device:

w conversion loss

w conversion compression

namplitude and phase tracking

T&pical Test Setup

Figure 6-60 shows a typical test setup using frequency offset mode. Instructions are provided in Chapter 3, “Making Mixer Measurements. n The attenuators shown reduce mismatch uncertainties. The low pass filter keeps unwanted mixing products out of the sampler.

6-120 ApplicationandOperationConcepts