Why Can't My 8922 Measure Audio Frequency Anywhere Near the 400kHz Quoted in the Spec's?

This is because the default instrument state includes a 15kHz LPF in the audio path. To measure higher frequencies requires this filter to be removed.

If the 8922 is operated in 'G' or 'E' mode, going to the CW meas/AF analyzer screen gives you the opportunity to change the audio filter settings. The Audio filter 2 should be set to >99kHzLPF. Audio frequencies at 400kHz can now be measured.

With the addition of the new user interface on the 8922H/F then subsequently 8922M/S the audio screen format was changed. There is now no provision to alter the audio filter setting from the default value. This decision was made as it was felt unlikely people would need the capability. However it can still be achieved by changing the aud1_filter_2 latch to '1' on the Service screen.