Second Harmonic Distortion (Shd); Test Limits - Keysight N9000A 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 –30 dBm signal at the input mixer, the distortion product should be
suppressed by > –65 dBc.
The equivalent Second Harmonic Intercept (SHI) is 35 dBm (–30 dBm + 65 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, 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) Frequency: 10 to 40 MHz
Filter, 50 MHz Low Pass
Synthesized Sweeper
298
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
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
Mixer Level Distortion
–10 dBm < –55 dBc
Recommended
Agilent Model
1250-1476
1250-1200
83059B
10503A
0955-0306
PSG
Chapter 15