Agilent
N8973A, N8974A, N8975A
NFA Series Noise Figure Analyzers
Data Sheet
1. The N8974A and N8975A models have a mechanical switch fitted. This switch allows the analyzers to change between the 10 MHz to 3.0 GHz
and the 3.0 GHz to 6.7 GHz frequency range on the N8974A. On the N8975A, the switch allows the change between the 10 MHz to 3.0 GHz and the 3.0 GHz to
26.5 GHz frequency range. If the current measurement frequency range crosses the 3.0 GHz point, the switch will operate. The mechanical switch has a limited
number of cycles over which it is reliable. To maximize the reliable life of the switch, switching over the 3.0 GHz frequency point should be kept to a minimum.
2. Temperature stability on the standard frequency reference is achieved 60 minutes after the analyzer is turned on.
3. Option 1D5 recommended for applications requiring high frequency stability.
4. Parts Per Million (10
-6
).
5. Tuning accuracy is dependent on measurement bandwidth.
2
Specifications
Specifications are only valid for the stated operating frequency, and apply over
0° C to +55° C unless otherwise noted. The analyzer will meet its specifications
after 2 hours of storage within the operating temperature range, 60 minutes after
the analyzer is turned on, with Alignment running. A user calibration is required
before corrected measurements can be made.
Frequency
Frequency range
1
N8973A 10 MHz to 3.0 GHz
N8974A 10 MHz to 6.7 GHz
N8975A 10 MHz to 26.5 GHz
Measurement bandwidth (nominal)
N8973A, N8974A, N8975A 4 MHz, 2 MHz, 1 MHz, 400 kHz, 200 kHz, 100 kHz
Frequency reference
Standard
2
Opt.1D5
3
Aging ± < 2 ppm4/year ± < 0.1 ppm/year
Temperature stability ± < 6 ppm ± < 0.01 ppm
Settability ± < 0.5 ppm ± < 0.01 ppm
Tuning Accuracy5(Start, Stop, Center, Marker)
4MHz measurement Bandwidth (default on all models of Noise Figure analyzer)
Frequency Error
10MHz – 3.0 GHz ± < Reference error + 100 kHz
3.0GHz – 26.5 GHz ± < Reference error + 400 kHz
< 4 MHz- Measurement Bandwidth (functionality not present in N8972A)
Frequency Error
10MHz – 3.0 GHz < ± Reference error + 20 kHz
3.0GHz – 26.5 GHz < ± Reference error + 20% of measurement bandwidth
Noise figure and gain
Performance is dependent on the ENR1of the noise source used:
N8973A, N8974A and N8975A Noise source ENR
(10 MHz to 3.0 GHz) 4-7 dB 12-17 dB 20-22 dB
Noise figure Measurement range 0 to 20 dB 0 to 30 dB 0 to 35 dB
Instrument uncertainty ± < 0.05 dB ± < 0.05 dB ± < 0.1 dB
Gain
2
Measurement range -20 to +40 dB
Instrument uncertainty ± < 0.17 dB
N8974A and N8975A Noise source ENR
(>3.0 GHz) 4-7 dB 12-17 dB 20-22 dB
Noise figure Measurement range 0 to 20 dB 0 to 30 dB 0 to 35 dB
Instrument uncertainty ± < 0.15 dB ± < 0.15 dB ± < 0.2 dB
Gain
2
Measurement range -20 to +40 dB
Instrument uncertainty ± < 0.17 dB
Instrument’s noise figure
3
1. Excess Noise Ratio
2. For measurement bandwidths below 4 MHz, and spacing between measurement points below 3 MHz,
gain uncertainty may increase to a maximum of ± 0.7 dB.
Frequency Noise figure Noise figure over a limited
temperature range of 23° C ± 3° C
> 3.0 GHz to 13.2 GHz < 12.0 dB < 10.5 dB
> 13.2 GHz to 26.5 GHz < 16.0 dB < 12.5 dB
Characteristic1noise figure at 23° C ±3° C (10 MHz to 3.0 GHz)
Characteristic
1
noise figure at 23° C ±3° C (3.0 GHz to 26.5 GHz)
Maximum external gain between noise source output and RF input
2
> 65 dB
Averaging
Up to 999 measurement results
Jitter
3
Jitter with no averaging
4
5 dB Y-factor standard deviation < 0.1 dB
4
1. Characteristic values are met or bettered by 90% of instruments with 90% confidence.
2. Subject to maximum operating input power.
3. Specified for a 4 MHz measurement bandwidth. Jitter in noise figure is equivalent to jitter in Y-factor to within 10% for ENR > 14 dB and F < 4 dB.
At minimum smoothing, jitter can limit accuracy; the small jitter at high smoothing does not.
4. For true Gaussian noise, jitter reduces with increased averaging typically by a factor of 1/√(number of averages).
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