10. Residual FM, HP 8591EM

Part 2: Narrow Bandwidth Residual FM

The following procedure is an additional test for testing the residual FM of EMC analyzers in narrow bandwidths. Perform \Part 1: Residual FM" before performing this procedure.

Determining the IF Filter Slope

1.Press 4PRESET5 on the EMC analyzer, then wait for the preset routine to ￿nish. Set the EMC analyzer by pressing the following keys:

4FREQUENCY5 500 4MHz5

4SPAN5 1 4MHz5

4AMPLITUDE5 98 4dB￿V5

SCALE LOG LIN (LOG) 1 4dB5

4MKR !5 MKR ! HIGH

4MKR5 More 1 of 3 MK TRACK ON OFF (ON)

4SPAN5 300 4Hz5

2.Wait for the AUTO ZOOM message to disappear. Press the following EMC analyzer keys:

4MKR !5 More 1 of 3 MARKER !REF LVL

4MKR5 MARKER 1 ON OFF (OFF)

4BW5 30 4Hz5

4SGL SWP5

3. Wait for the completion of a new sweep on the EMC analyzer, then press:

4MKR !5 MKR ! HIGH

More 1 of 3 More 2 of 3 MARKER 1

4.Rotate the EMC analyzer knob counterclockwise until the MKR-1 amplitude reads 01 dB 60.2 dB. Press MARKER 1 . Rotate the knob counterclockwise until the MKR-1 amplitude reads 04 dB 60.3 dB.

5.Divide the MKR-1 frequency (in hertz) by the MKR-1 amplitude (in dB) to obtain the slope of the IF bandwidth ￿lter.

For example, if the MKR-1 frequency is 1.08 kHz and the MKR-1 amplitude is

3.92 dB, the slope would be equal to 275.5 Hz/dB. Record the result below:

2-48 Performance Veri￿cation Tests