298 Chapter 15
Functional Tests
Second Harmonic Distortion (SHD)
Second Harmonic Distortion (SHD)
Test Lim its
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).
Applied Frequency Mixer Level Distortion
40 MHz –10 dBm < –55 dBc
Item
Critical Specifications
(for this test)
Recommended
Agilent Model
Adapter, Type-N(m) to BNC(f) Frequency: 10 MHz to 80 MHz
VSWR: < 1.05:1
1250-1476
Adapter, BNC(f) to SMA(m) Frequency: 40 to 80 MHz 1250-1200
Adapter,
3.5 mm(f) to 3.5 mm(f)
Frequency: 10 MHz to 80 MHz
VSWR: < 1.1:1
83059B
Cable, BNC 120 cm (2 required) Frequency: 10 to 40 MHz 10503A
Filter, 50 MHz Low Pass Cutoff Frequency: 50 MHz
Rejection at 65 MHz: > 40 dB
Rejection at 75 MHz: > 60 dB
0955-0306
Synthesized Sweeper Frequency: 50 MHz
Spectral Purity: Better than –30 dBc
PSG
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