Hewlett Packard 491C
Microwave Amplifier
Product Description:
Amplification of frequencies from 1 to 12.4 GHz is accomplished in four ranges
by the Hewlett-Packard microwave amplifiers. Each delivers at least 1 watt with
an input of 1 mW or less, a gain of at least 30 dB.
Amplitude modulation circuitry has been designed for wide bandwidth (down to dc)
and with internal amplification, so that small modulation signals cause a large output
power change. This unique modulation circuitry also permits power leveling with
external elements, plus remote programming. Spurious phase modulation of 0.1o or less and residual AM at least 45 dB below carrier
are assured by regulation of the filament, anode, and helix power supplies. TWT
cathode current is monitored by a front-panel meter and can be controlled by the
gain adjustment for rated power output or for reducing tube current to extend tube
life when full output power is not required. Helix collector and anode current can
be measured at an easily accessible test point board.
Product Specifications:
| Frequency range (GHz): |
2-4 |
| Power output (with 1 mW or less input): |
1W |
| Gain at rated output: |
30 dB |
| Gain variation with freq: |
at rated output small signal: |
</=6 dB |
| across any 10% of band |
</=5 dB |
| across full band |
</=10 dB |
| Gain variation with +/-10% variation from rated line voltage: |
</=1dB |
| Noise: |
max. noise figure |
30 dB |
| typ. noise power out |
-10 dBm |
For All Models:
| Maximum RF input: |
100 mW. |
| Input/output characteristics: |
impedance, 50 ohms; reflection coefficient (cold), </=0.43 (2.5 SWR, 7.3 dB return
loss); connectors, type N female. |
|
AMPLITUDE MODULATION
|
| Sensitivity: |
a modulation input -20 V peak or more reduces the RF output by more than 20 dB from
dc to 50 kHz. Above 50 kHz modulation decreases approximately 6 dB per octave. |
| Frequency response: |
dc to 500 kHz (3dB). |
| Input impedance: |
100 k ohms shunted by approx. 50 pF. |
| Pulse response: |
<1 micro s rise and fall times. |
| Residual AM: |
at lease 45 dB below carrier. |
| Dimensions: |
16-3/4" wide, 5-1/2" high, 18-3/8" deep (426 x 141 x 467 mm) |
| Power: |
115 or 230 volts +/-10%, 50 to 60 Hz, approx. 225 watts. |
Available for rent from 
Test Equipment
Corporation.
For more information E-Mail sales@testeq.com
or call (800)TEC-DOES.
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