OIP2 OIP3 Example
Measure LPF Attenuation at OIP3 and OIP2 Frequencies
Set Amplifier Tones to 0dBm
DG-1032 -> Combiner -> Amplifier -> 20 dB Pad -> SSA3021X
Measure Amplifier OIP3 and OIP2
DG-1032 -> Combiner -> Amplifier -> 20 dB Pad -> LPF -> SSA3021X
- OIP3 = (61.61 - .77) / 2 = +30.4dBm
- OIP2 = (42.40 - .90) = +41.5dBm
- Guideline: OIP value 10dB above noise floor
Limits OIP3 range to ((75-10)-.77) / 2 ~= +32dBm
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Measure Amplifier OIP3 with Pre-Amp
DG-1032 -> Combiner -> Amplifier -> 20 dB Pad -> LPF -> SSA3021X
- OIP3 = (61.9 - .77) / 2 = +30.6dBm
- Guideline: OIP value 10dB above noise floor
Limits OIP3 range to ((90-10)-.77) / 2 ~= +40dBm
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Measure Amplifier OIP3 with Pre-Amp and Narrow BW
DG-1032 -> Combiner -> Amplifier -> 20 dB Pad -> LPF -> SSA3021X
- BW = 1kHz
- OIP3 = (61.8 - .77) / 2 = +30.5dBm
- Guideline: OIP value 10dB above noise floor
Limits OIP3 range to ((110-10)-.77) / 2 ~= +50dBm
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Evaluate SSA3021X OIP With and Without LPF
Set Tones to 0dBm
DG-1032 -> Combiner -> 20 dB Pad -> SSA3021X
Zoom into 2.87MHz, Add LPF and Measure OIP
- DG-1032 -> Combiner -> 20 dB Pad -> LPF -> SSA3021X
- Enable SSA3021X PreAmp
- Set BW = 10Hz
- Test bench OIP3 = (111.79 - .77) / 2 = +55.5dBm
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Low Level Settings
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- Test Amplifier
- DG1032 Settings
- CH1 = 5MHz at -20dBm
- CH2 = 6MHz at -20dBm
- Utility Ampl Cpl = On
- SSA Marker Settings
- Marker 1 = 5MHz Delta Pair, Relative 2
- Marker 2 = 6MHz
- Ref Offest = Combiner + Attenuator
- Marker 1Δ2 = Amplifier Gain = 16.1dB
- Marker2 value = signal generator output level = -20dBm
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Measure P1dB
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- Increase DG1032 output level for DUT 1dB Gain compression
Marker 1Δd2, = 15.1dB
- P1dB = Marker 1r, DUT output level, = 15.2dBm
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Measure SA NF
Measure SA+DUT NF
Amp NF = 2.94