2794

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The Tektronix 2794 is a spectrum analyzer with a frequency range of 10 kHz to 21 GHz in coax, to 325 GHz with external waveguide mixers. The minimum resolution bandwidth is 10 Hz, and provides measurement resolution proportional to the frequency accuracy or span. In addition to conventional digital storage features, non-volatile memory (NVRAM) stores up to 9 separate waveforms with their readouts and markers, for later recall for additional analysis and comparison. Also, store up to 10 different front-panel control setups for future recall. The instrument can selectively count one particular signal out of several that may be present at its input.

The single and delta markers provide direct readout of frequency and amplitude information of any point along any displayed trace. Or, get the relative (delta) frequency and amplitude information between any two points along any displayed trace or between traces.

Additional features include: Continuous Resolution Frequency Tuning, Up to 90 dB Viewable Dynamic Range, Built-in Frequency Counters Provide Frequency Determination to within 0.0000001%, Sensitivities to -134 dBm, Built-in Intelligence for Signal Processing/Marker Functions, Push Button Occupied-Bandwidth/Noise Normalization Functions, Macro Capability with Nonvolatile Memory, and Optional Switch-Selectable 50/75Ω Impedances.

Front panel inputs/outputs are: RF INPUT 50Ω N connector; EXTERNAL MIXER TNC connector (50Ω) ; 1ST LO OUTPUT SMA connector (Provides access to the output of the 1st local oscillator); 2ND LO OUTPUT SMA connector (Provides access to the output of the 2nd local oscillator); and CAL OUT BNC connector (Provides a 100 MHz ±10 Hz, -20 dBm ±0.3 dB signal).

Rear panel inputs/outputs are: PROBE POWER (Provides operating voltages for active probes); HORIZ|TRIG (EXT IN) BNC connector (A dual function connector: When in External Triggering mode the connector is an AC coupled input for trigger signals. When the TIME/DIV selection is EXT the connector is a DC coupled input for horizontal sweep voltages); MARKER|VIDEO (EXT IN) BNC connector (Interfaces to a Tektronix 1405 TV Adapter to display an externally-generated marker); HORIZ (OUTPUT) BNC connector (A dual function connector: Provides 110 MHz IF output as an input into the PEN LIFT connector. Alternately supplies a 0.5 V/div horizontal signal.); VERT (OUTPUT) BNC connector (Provides access to the video signal with 0.5 V for each division of displayed video above or below the center line.); PEN LIFT (OUTPUT) BNC connector (Provides access to a TTL compatible signal to lift the pen of a chart recorder during sweep retrace); 10 MHz IF (OUTPUT) BNC connector (Provides access to the output of the 10 MHz IF); EXT REF IN BNC connector (50Ω input for a 1, 2, 5, or 10 MHz ext ref signal); J104 ACCESSORY female DB25 connector (External inputs and outputs to instrument bus)); IEEE STD 488 PORT GPIB interface.

Key Specifications

Frequency	Coaxial Input Bands: 10 kHz to 21 GHz, External Waveguide mixer: 10 kHz to 325 GHz
Frequency Span	100 Hz to 150 GHz (plus 0 Hz and MAX)
Resolution Bandwidth	6 dB bandwidths from 3 Hz to 10 MHz
RF Input impedance	50 Ω
Maximum Safe Input Power	1 Watt (+30 dBm) CW, 75 W peak, 1 µs, 0.1% duty factor pulse
External Mixer Input	50 Ω with VSWR ≤1.3:1 at <2.5 GHz, and ≤3.5:1 at 21 GHz
RF Attenuator	0 dB to 60 dB, 10 dB steps
Reference Level	-117 dBm to +30 dBm
LO Output Power (2 to 6 GHz)	1st LO: +7.5 dBm to +20 dBm; 2nd LO: -12 dBm to +5 dBm
Sweep Speed	100 s to 200 µs in 1, 2, 5 sequence
Video Bandwidth	0.3 Hz to 30 kHz
Triggering Modes	Free Run, Line, Video, Single, Ext
Displayed Average Noise	−80 dBm to −134 dBm
Display Dynamic Range	90 dB
Dynamic Range (Compression to noise)	134 dBm
Weight	22.2 kg (48 lbs)
Power	90 − 132 VAC, 47 to 63 Hz; 180 – 250 VAC, 47 to 63 Hz. At 115 VAC, 60 Hz, 210 W max

Internals

The A54 memory board and A70 Z-axis board bear microswitches to select certain options or configure the respective cards for proper operation in the 2794. Switch position 5 on A70S1010 enables the service mode adjustments in the utility (UTIL) menu. For further info see the switch settings in the figure below.

Options

• Opt. 07: External Mixer input replaced by low frequency 75 Ω input (dBmV calibrated)
• Opt. 10: Frequency range extension to 26.5 GHz
• Opt. 11: Frequency range extension to 40 GHz
• Opt. 12: Frequency range extension to 60 GHz
• Opt. 13: Frequency range extension to 140 GHz
• Opt. 14: Frequency range extension to 325 GHz
• Opt. 23: GRASP software, PC2A interface, GPIB cable
• Opt. 30: Rackmount with handles for 19 in. rack
• Opt. 39: Non-lithium batteries for battery-backed memory
• Opt. 41: Digital Microwave Radio Measurement Enhancement Package
• Opt. 42: Replaces MARKER/VIDEO input port on the rear panel with a 110 MHz IF output port that provides a 3 dB signal bandwidth ≥4.5 MHz

Pictures

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  2794 front

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  2794 front

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  2794 front

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  2794 front

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  2794 rear with cover

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  2794 front

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  2794 rear without cover (note red voltage selector switch barely visible through plastic grill, top left)

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  2794 internal top

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  2794 internal bottom

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  A70 Z-axis & RF interface board 0671-2618-00 with S1010 switch and Elapsed time meter

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  Switch settings of A54A1050 and A70S1010 for the 2794.