49X Series Comparison
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.
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.
| 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+ |