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|introduced=1980  
|introduced=1980  
|discontinued=1993  
|discontinued=1993  
|designers=
|designers=Larry Lockwood;Steve Morton;Linley Gumm;Robert Alm;Bob Bales;Carlos Beeck;Bill Benedict;Craig Bryant;Russell Brown;Wes Hayward;David Leatherwood;Gordon Long;Dave Morton;Bill Peterson;David Shores;Steve Skidmore;Dennis Smith;Phil Snow;Leighton Whitset;Norman Witt;
|manuals=
|manuals=
'''492/492P'''
'''492/492P'''
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* [[Media:Tek_490-Series_Final Spec_1991.pdf| Tektronix 492 Final Spec]] (OCR)
* [[Media:Tek_490-Series_Final Spec_1991.pdf| Tektronix 492 Final Spec]] (OCR)
}}
}}
The '''Tektronix 492''' is a spectrum analyzer with a frequency range of 10 kHz to 21 GHz in coax, and up to 325 GHz with external waveguide mixers (492PGM N/A).  The '''P''' suffix designation indicates GPIB '''P'''rogrammability.  The minimum resolution bandwidth is 100 Hz, and provides measurement resolution proportional to the frequency accuracy or span.  With non-volatile memory (NVRAM) you can save up to 9 waveform displays, up to 10 complete front panel measurement parameter setups, and 8 K for programming macros of commonly used routines.
The '''Tektronix 492''' is a spectrum analyzer with a frequency range of 10 kHz to 21 GHz in coax, and up to 325 GHz with external waveguide mixers (492PGM N/A).  The '''P''' suffix designation indicates GPIB '''P'''rogrammability.   


During the lifespan of the instrument the specifications and included options were altered several times. A major upgrade was the introduction of the '''492A''' in 1987 which added marker functionality and resolution bandwidths and the '''492BP''' in 1989 which added a counter and increased the displayed dynamic range. The '''492PGM''' is a cost reduced version introduced in 1990. Also see [[49X Series Comparison]].
During the lifespan of the instrument, the specifications and included options were altered several times. A major upgrade was the introduction of the '''492A''' in 1987 which added marker functionality and resolution bandwidths and the '''492BP''' in 1989 which added a counter and increased the displayed dynamic range. The '''492PGM''' is a cost reduced version introduced in 1990. Also see [[49X Series Comparison]].
 
Regarding the 492, [[Linley Gumm]] says,
<blockquote>
Given how complicated it was,  many people contributed to the design.  I currently have a list of 20 people. 
The problem is that I’m sure that I am missing several people and I hate to submit a list without them.
 
The 492 was designed at the request of the military.  They asked for a modern replacement of the [[491]]. 
It was required that it provide coaxial input coverage of the lower microwave bands (~18 GHz),
be very rugged, be a one person carry and fit through a submarine hatch. 
There was a lot more than that of course. 
 
When the 492 program started I was the project leader of the [[7L18]] and was still working to finish it off. 
The 7L18 was the first instrument at Tektronix to use a microprocessor. 
We had worked long and hard to learn how to electronically switch and control all the elements that were controlled by physical switch closures in the earlier instruments. 
 
Understand that to position the frequency of a YIG filter correctly with respect to the frequency of a YIG oscillator
one must generate very quiet DC voltages accurate to roughly 1 part in 20,000 (i.e. 1 MHz in 18 GHz), so new control techniques were required. 
Plus the TEK-made YIG filter designed for the 7L18 was therefore ready for use in the 492. 
 
We had also learned quite a number of things not to do and this was also used to anchor the 492 program. 
I say this to note that most of the long lasting, “classic”, Tektronix products were often the second, but more often the third generation product by the same design group. 
The 492 was definitely a second generation product in its use of microwave components and a microprocessor based control system;
perhaps a third if you lump the [[7L12]], [[7L13]] (microwave systems) and the [[7L5]] (electronic bus control system) together as a first generation.
 
[[Larry Lockwood]] led the first part of the program.  He defined the RF and microwave frequency conversion architecture of the 492. 
As the program progressed, [[Steve Morton]] became the project manager of the initial 492 program. 
Recognize that beyond that initial project, follow-on design work went on for years as new features were added. 
Further, after their initial design work in the initial portion of the project, designers often went on to do rather different subsystems in the follow-ons.
 
I worked on the 492 as a circuit designer in the initial design and in several other roles later, none of which were leadership roles.
 
The other people I can recall having worked on the 492 at some point in its life were:
[[Robert Alm]],
[[Bob Bales]],
[[Carlos Beeck]],
[[Bill Benedict]],
[[Craig Bryant]],
[[Russell Brown]],
[[Wes Hayward]],
[[David Leatherwood]],
[[Gordon Long]],
[[Dave Morton]],
[[Bill Peterson]],
[[David Shores]],
[[Steve Skidmore]],
[[Dennis Smith]],
[[Phil Snow]],
[[Leighton Whitset]], and
[[Norman Witt]].
 
Be aware my spelling is often “inventive”.  There are at least two other names I can’t bring to mind.
</blockquote>


{{BeginSpecs}}
{{BeginSpecs}}
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* Coaxial Input Bands: 10 kHz to 21 GHz
* Coaxial Input Bands: 10 kHz to 21 GHz
* External Waveguide mixers: 10 kHz to 325 GHz (applies to 492BP not 492PGM) }}  
* External Waveguide mixers: 10 kHz to 325 GHz (applies to 492BP not 492PGM) }}  
{{Spec | Frequency Span (plus 0 Hz and MAX) | 492BP: 100 Hz/div to 10 GHz/div; 492PGM: 200 MHz to 1 GHz; both in 1, 2, 5 sequence }}  
{{Spec | Frequency Span | 492BP: 100 Hz/div to 10 GHz/div; 492PGM: 200 MHz to 1 GHz; both in 1, 2, 5 sequence; plus 0 Hz and MAX }}  
{{Spec | Resolution Bandwidth (-6 dB bandwidth) | 492BP: 100 Hz to 3 MHz; 492PGM: 1 kHz to 3 MHz; both in decade steps }}  
{{Spec | Resolution Bandwidth (-6 dB bandwidth) | 492BP: 100 Hz to 3 MHz; 492PGM: 1 kHz to 3 MHz; both in decade steps }}  
{{Spec | RF Input impedance | 50 Ω }}
{{Spec | RF Input | 50 Ω, max. +30 dBm (1 W) CW; / 75 W peak pulse (1 µs, 0.1% duty factor) }}
{{Spec | Maximum Safe Input Power | CW: +30 dBm (1 W); Pulse: 75 W Pk (1 µS pulse, 0.1% duty factor) }}
{{Spec | RF Attenuator | 0 dB to 60 dB, 10 dB steps }}
{{Spec | RF Attenuator | 0 dB to 60 dB, 10 dB steps }}
{{Spec | Reference Level | -117 dBm to +30 dBm }}  
{{Spec | Reference Level | -117 dBm to +30 dBm }}  
{{Spec | Sweep Speed | 10 sec/div to 20 µs/div, 1−2−5 }}
{{Spec | Sweep Speed | 10 sec/div to 20 µs/div, 1−2−5 }}
{{Spec | Video Bandwidth | 492BP: 0.3 Hz to 30 kHz; 492PGM: 3 Hz to 30 kHz }}  
{{Spec | Video Bandwidth | 492BP: 0.3 Hz to 30 kHz; 492PGM: 3 Hz to 30 kHz }}  
{{Spec | Memory | NVRAM for up to 9 waveform displays, up to 10 front panel setups, plus 8 K for programming macros
}}
{{Spec | Triggering Modes | Free Run, Line, Video, Single, External }}
{{Spec | Triggering Modes | Free Run, Line, Video, Single, External }}
{{Spec | Displayed Average Noise | −30 dBm to −131 dBm }}
{{Spec | Displayed Average Noise | −30 dBm to −131 dBm }}
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* Opt. 02: Digital Storage. Later became standard
* Opt. 02: Digital Storage. Later became standard
* Opt. 03: Frequency Stabilization & 100 Hz Resolution. Later became standard
* Opt. 03: Frequency Stabilization & 100 Hz Resolution. Later became standard
* Opt. 07: 75Ω dBmV input and calibration in addition to the normal 50Ω dBm input and calibration.  (Not combinable with Opt. 21 and 22; no external mixer capability).  Include 42-inch 75Ω BNC-BNC coax cable and BNC male to “F” female adapter.
* Opt. 07: 75 Ω dBmV input and calibration in addition to the normal 50 Ω dBm input and calibration.  (Not combinable with Opt. 21 and 22; no external mixer capability).  Include 42-inch 75 Ω BNC-BNC coax cable and BNC male to “F” female adapter.
* Opt. 21: (492BP) High performance 18 to 40 GHz WM490 Series Waveguide Mixer Set
* Opt. 21: (492BP) High performance 18 to 40 GHz WM490 Series Waveguide Mixer Set
* Opt. 22: (492BP) Same as Opt. 21 plus WM490U (40-60 GHz) Waveguide Mixer
* Opt. 22: (492BP) Same as Opt. 21 plus WM490U (40-60 GHz) Waveguide Mixer
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* [https://www.youtube.com/watch?v=tKC24SpHTSY YouTube: Tektronix 492 and 496 Portable Spectrum Analyzers]
* [https://www.youtube.com/watch?v=tKC24SpHTSY YouTube: Tektronix 492 and 496 Portable Spectrum Analyzers]
* [[067-1137-99|067-1137-99 GPIB to accessory controller]]  
* [[067-1137-99|067-1137-99 GPIB to accessory controller]]  
{{Documents|Link=492}}


==Connections==
==Connections==
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