Figure 17. Intermodulation distortion products.

TB 9-6625-1914-24

(6) Carefully adjust amplitudes of function generator no. 2 and signal generator so

that both signal peaks are 3 dB below LOG REF graticule on display screen. The

signals at 140 kHz (2f1) and 180 kHz (2f2) (fig. 17) are second order harmonics. Any

second order intermodulation product (due to analyzer) will occur at 160 kHz (f1 + f2).

Any third order intermodulation products will occur at 50 kHz (2f1-f2) and at 110 kHz

(2f2-f1). The intermodulation products should be below -70 dB graticule line.

(7) Repeat technique of (4) through (6) above with function generator no. 2 at a

frequency of 1.7 kHz and signal generator at a frequency of 2 kHz.

(8) Position SCAN WIDTH PER DIVISION switch to 500 Hz and BANDWIDTH

switch to 30 Hz for model 8552B or 50 Hz for model 8552A. Set SCAN WIDTH to 0-10f.

NOTE

It may be necessary to tune ZERO ADJ control until local

oscillator feed-through is centered at far left graticule line.

(9) Adjust function generator no. 2 and signal generator controls to set both signal

peaks 3 dB below LOG REF graticule on display screen. The signals at 3.4 kHz (2f1)

and 4.0 kHz (2f2) are second order harmonics (fig. 17).

Any second order

intermodulation product (due to analyzer) will occur at 3.7 kHz (2f1-f2). Any third order

intermodulation product will occur at 1.4 kHz (2f1-f2) and at 2.3 kHz (2f2-f1). All

intermodulation products should be below -60 dB graticule line.

b. Adjustments. No adjustments can be made.

Figure 17. Intermodulation distortion products.