49X Series Comparison

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This page is an attempt to compare the 49X, 275X, and 279X series spectrum analyzers that share many common hardware features. All data is for the base model without options. The 491 that number wise fits the 49X-series is an entirely different instrument and consequently not covered here.

Comparison Table

Model 492 492A 492BP 492PGM 494 494A 495 496 497P 2753P 2754 2755 2755AP 2756P 2792 2794 2795 2797 Notes
Frequency Range 50 kHz – 21 GHz 50 kHz – 21 GHz 10 kHz – 21 GHz 10 kHz – 21 GHz 10 kHz – 21 GHz 10 kHz – 21 GHz 100 Hz – 1.8 GHz 1 kHz – 1.8 GHz 100 Hz – 7.1 GHz 100 Hz – 1.8 GHz 50 kHz – 21 GHz 10 kHz – 21 GHz 10 kHz – 21 GHz 10 kHz – 21 GHz 10 kHz – 21 GHz 10 kHz – 21 GHz 100 Hz – 1.8 GHz 100 Hz – 7.1 GHz
Min. Span 100 kHz 200 Hz 1 kHz 2 kHz 500 Hz 100 Hz 100 Hz 500 Hz 1 kHz 10 Hz 200 Hz 200 Hz 100 Hz 10 Hz 2 kHz 100 Hz 100 Hz 100 Hz
Max. Span 5 GHz 10 GHz 100 GHz 10 GHz 5 GHz 100 GHz 1 GHz 1 GHz 5 GHz 100 MHz 1 GHz 10 GHz 10 GHz 10 GHz 12 GHz 150 GHz 1.7 GHz 4 GHz
Ext. Mix Yes Yes Yes No Yes Yes No No No No No Yes Yes Yes Yes Yes No No
Center Frequency Accuracy ±5 MHz ±30 kHz ±21 kHz ±30 kHz Freq.Ref. ±20 kHz ±20 kHz ±5 MHz ±21 kHz ±20 kHz ±30kHz ±30kHz ±20 kHz ±20 kHz ±30kHz ±20 kHz ±20 kHz ±21 kHz at 1 GHz, 100 kHz/div span
Frequency Reference Accuracy 1×10-6/year 1×10-5/year 1×10-7/year 1×10-7/year 1×10-7/year 1×10-6/year 1×10-7 /year ? ? 5×10-7 /year 1×10-7 /year ? 1×10-7/year 1×10-7/year ?
SSB Phase Noise −105 dBc/Hz −105 dBc/Hz −103 dBc/Hz −90 dBc/Hz −105 dBc/Hz −105 dBc/Hz −105 dBc/Hz -105 dBc/Hz -103 dBc/Hz -105 dBc/Hz -105 dBc/Hz -105 dBc/Hz −103 dBc/Hz −105 dBc/Hz −105 dBc/Hz −105 dBc/Hz 30kHz offset, N=1
Min. Resolution Bandwidth 1 kHz 100 Hz 100 Hz 1 kHz 30 Hz 10 Hz 10 Hz 30 Hz 10 Hz 10 Hz 1 kHz 100 Hz 100 Hz 10 Hz 1 kHz 10 Hz 10 Hz 10 Hz
Max. Resolution Bandwidth 1 MHz 1 MHz 3 MHz 3 MHz 1 MHz 3 MHz 3 MHz 1 MHz 3 MHz 3 MHz 1 MHz 1 MHz 3 MHz 3 MHz 3 MHz 3 MHz 3 MHz 3 MHz
Dynamic Range 80 dB 80 dB 90 dB 80 dB 80 dB 90 dB 80 dB 80 dB 90 dB 90 dB 80 dB 80 dB 90 dB 90 dB 90 dB 90 dB 90 dB 90 dB
GPIB P model P model yes yes P model P model P model P model Yes Yes P model P model Yes Yes Yes Yes Yes Yes
Marker No Yes Yes Yes No Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes
Counter No No Yes No Yes Yes Yes No Yes Yes No No Yes Yes Yes Yes Yes Yes
Introduced 1980 1987 1989 1990 1985 1988 1987 1982 1990 1988 1987 1987 1989 1988 1993 1993 1993 1993

Common Features

The frequency conversion is identical for all models and based on two tunable local oscillators. The frequency coverage is split in several bands, where band 1 is selected with electromechanical switches. Therefore none of the members of the 49X, 275X, and 279X families allow for a span exceeding the band 1 limits, as this would require continuous electromechanical band-switching. As a new feature the 279X-family allows for a multiband sweep mode displaying a sweep over bands 2-5. For bands 4 and higher the mixer is operated as a harmonic mixer, which results in a degradation of the analyzers phase noise performance for frequencies exceeding 7.1 GHz. Bands 6-12 require external mixers of the WM490 family or WM780 family.

Band Frequency Range (GHz) 1st IF LO Range (MHz) LO Multiplier
1 0 − 1.8 2072 2072 − 3872 1-
2 1.7 − 5.5 829 2529 − 6329 1-
3 3 − 7.1 829 2171 − 6276 1+
4 5.4 − 18 829 2076 − 6276 3-
5 15 - 21 2072 4309 − 6309 3+
6 18 - 27 2072 2655 − 4155 6+
7 26 - 40 2072 2393 − 3793 10+
8 33 - 60 2072 3093 − 5793 10+
9 50 - 90 2072 3195 − 5862 15+
10 75 - 140 2072 3171 − 5997 23+
11 110 - 220 2072 2917 − 5890 37+
12 170 - 325 2072 2999 − 5767 56+

Accessories

  • TR503 dc − 1.8 GHz tracking generator
  • 1405 sideband adapter
  • WM490 external mixer
  • WM780 external mixer (individually calibrated)

Links