Second Harmonic Distortion (Shd) - Keysight N8973B Service Manual

Functional Tests

Second Harmonic Distortion (SHD)

Second Harmonic Distortion (SHD)
Test Limits
This test checks the second harmonic distortion of the signal 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 signal
analyzer to prevent the source 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 –15 dBm signal at the input mixer, the distortion product
should be suppressed by > –60 dBc.
The equivalent Second Harmonic Intercept (SHI) is 45 dBm
(–15 dBm + 60 dBc). This test is performed with –10 dBm at the mixer and
verifies the distortion product is suppressed by –55 dBc. This ensures the SHI is
also 45 dBm (–10 dBm + 55 dBc).
Item
Adapter, Type-N (m) to
BNC (f)
Adapter, BNC (f) to
SMA (m)
Adapter,
3.5 mm (f) to 3.5 mm (f)
Cable, BNC 120 cm
(2 required)
Filter, 50 MHz Low Pass
Synthesized Sweeper
498
Applied Frequency
40 MHz
Critical Specifications
(for this test)
Frequency: 10 MHz to 80 MHz
VSWR: < 1.05:1
Frequency: 40 to 80 MHz
Frequency: 10 MHz to 80 MHz
VSWR: < 1.1:1
Frequency: 10 to 40 MHz
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
Keysight NFA Series Noise Figure Analyzers Service Guide
Mixer Level Distortion
–10 dBm < –55 dBc
Recommended
Keysight Model
1250-1476
1250-1200
83059B
10503A
0955-0306
PSG