44. Residual Responses, HP 8591EM

12.Press 4FREQUENCY5, then adjust the center frequency until the LO feedthrough (the \signal" near the left of the screen) is just o￿ the left-most vertical graticule line. Press the following EMC analyzer keys:

4FREQUENCY5 CF STEP AUTO MAN (MAN) 9.8 4MHz5

4DISPLAY5 DSP LINE ON OFF (ON) 17 4dB￿V5

Add 17 dB￿V to the MEAS UNCAL Amplitude Error (recorded in step 8), then set the display line to this value.

For example, if the amplitude error in step 8 is 019.5 dB, add 17 dB￿V to this value for a result of 02.5 dB￿V. Enter 02.5 dB￿V as the display line value.

13.Press 4SGL SWP5 and wait for a new sweep to ￿nish. Look for any residual responses at or above the display line.

If a residual is suspected, press 4SGL SWP5 again. A residual response will persist on successive sweeps, but a noise peak will not. Note the frequency and amplitude of any residual responses above the display line and to the right of the marker in Table 2-55.

14.Press 4FREQUENCY5, then 4 * 5 (step-up key) to step to the next frequency and repeat

step 13.

15.Repeat step 14 until the range from 1 MHz to 1.8 GHz has been checked. (This requires 183 additional steps.)

Table 2-55.

Residual Responses above Display Line Worksheet

 

Frequency

 

Amplitude

 

(MHz)

 

(dB￿V)

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Performance Veri￿cation Tests 2-301