Second Harmonic Distortion (Shd); Test Limits; Test Description - Agilent Technologies PSA Series Manual

PSA Functional Tests

Second Harmonic Distortion (SHD)

Second Harmonic Distortion (SHD)

Test Limits

Applied Mixer
Frequency
40 MHz –20 dBm

Test Description

This test checks the second harmonic distortion of the spectrum analyzer by tuning to
twice the input frequency and examining the level of the distortion product. A low pass
filter is inserted between the source and the spectrum analyzer to prevent the second
harmonic from artificially raising the second harmonic product displayed on the analyzer.
The power level at the input mixer is 20 dB higher than specified to allow the distortion
product to be seen. For example, the instrument specification may state that with a
–40 dBm signal at the input mixer, the distortion product should be suppressed by
> –75 dBc.
The equivalent Second Harmonic Intercept (SHI) is 35 dBm (–40 dBm + 75 dBc). This test
is performed with –20 dBm at the mixer and verifies the distortion product is suppressed
by –55 dBc. This ensures the SHI is also 35 dBm (–20 dBm + 55 dBc).
Item
Adapter
Adapter
Cable
Cable
Filter, 50 MHz Low
Pass
Synthesized Sweeper
136
Distortion
Level
< –55 dBc
Critical Specifications
(for this test)
Type-N(m) to BNC(f)
BNC(m) to SMA(f)
APC 3.5 mm, 1 meter
BNC, 120 cm
Cutoff Frequency: 50 MHz
Rejection at 65 MHz: > 40 dB
Rejection at 75 MHz: > 60 dB
Frequency: 50 MHz
Spectral Purity: Better than –30 dBc
Recommended
Agilent Model
1250-1476
1250-1700
8120-4921
10503A
0955-0306
83630B
Chapter 3