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HEWLETT-PACKARD


JOURNAL
T E C H N I C A L I N F O R M A T I O N F R O M T H E - h p - L A B O R A T O R I E S Vol.7 No. 9-10

PUBLISHED BY THE HEWLETT-PACKARD COMPANY, 275 PAGE MILL ROAD, PALO ALTO, CALIFORNIA MAY-JUNE, 1956




A New 10-15.5 KMC 10 MW Signal Generator
THE new -hp- Model 626A SHF Signal Gen frequency dial accurate within 1%, a direct-
erator operates over the range from 10 to reading attenuator with a 100 db range, and
15.5 kilomegacycles and provides a high out a flexible modulator that provides internal
put of many milliwatts over this range. Al square-wave, pulse or f-m modulation of the
though the generator is rated as providing a output signal. The new generator has been de
maximum of at least 10 mil veloped as a companion to the recently-devel
SEE ALSO liwatts over the whole oped -hp- 15-21 kmc generator'.
"Simple Regulated
Power Supply", p. 3 range, it usually provides Fig. 2 shows the generator's circuit arrange
"Obtaining Balanced
Square Waves", p. 4 more than 15 milliwatts at ment. The oscillator klystron operates with an
all frequencies and over external resonator which is tuned with a non-
most of the range the output is in the 30- milli contacting type plunger. Oscillator tube life
watt or higher region. The generator is thus is thus unrelated to the number of times the
valuable as a signal source for rough test work instrument is tuned through its frequency
as well as for reflectometer, slotted line, and re range. Repeller voltage is automatically
ceiver applications. tracked with the frequency dial so that no re-
In addition to its relatively high maximum peller voltage adjustments are required.
power output, the generator has the other fea The path from the klystron to the output
tures that make any signal generator conven terminals is all contained in wave guide. The
ient to use. These include a direct-reading klystron is followed by an uncalibrated wave
guide attenuator which serves to adjust the
power level applied to the main calibrated at
tenuator. This reference level is designed to
be 10 milliwatts, and the attenuator calibration
is based on a 10-milliwatt reference level. As
mentioned earlier, however, much higher pow
ers can be obtained when desired by operating
the instrument with both attenuators set for
minimum loss. The level at the input to the
main attenuator is monitored by a compen
sated thermistor bridge which operates a panel
meter. A wave guide directional coupler of the
-hp- multi-hole type- splits off a sample of the
power applied to the output attenuator for
Fig. 1. New -hp- Model 6 26 A SHF Signal Generator
monitoring purposes.
has high power output over 10 to i 5.5 kmc range, is >Wm. Hew Myers, The New -lip- 15-21 KMC 10 MW Signal Generator, Hew
provided u'ith direct-reading frequency dial and out lett-Packard Journal, Volume ?, No. 10, June, 1955.
put attenuator, has flexible modulator. 'E. F. Burnett and J. K. Hunton, A Precision Directional Coupler Using
Multi-Hole Coupling, Hewlett-Packard Journal. Volume 3, No 7-8 lUarc/i-
April, 1952.



P R I N T E D I N U . S . A . C O P Y R I G H T 1 9 5 6 H E W L E T T - P A C K A R D C O .