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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. 3 No. 9-10
PUBLISHED BY THE HEWLETT-PACKARD COMPANY, 395 PAGE MILL ROAD, PALO ALTO, CALIFORNIA MAY-JUNE, 1952
The -hp- Direct -Reading UHF Signal Generators
THE -hp- Model 616A UHF Signal Gen Both generators provide c-w, pulse, and
erator was designed as the first commer f-m type outputs. A versatile internal pulser
cially-available direct-reading signal gener permits the pulse modulation to meet a va
ator for the upper UHF region. It operates riety of requirements as to pulse rate, pulse
over the range from 1800 to 4000 megacy length, and synchronization. The character
cles. A second generator, the -hp- Model of typical output pulses is illustrated in Fig. 2.
614A, was subsequently developed for use Probably the most common use for signal
over the 800 to 2100 megacycle range as a generators is in testing receivers. For re
companion instrument for the 61 6 A. The ceiver testing, it is desirable that the output
6l4A and 6l6A are similar in all character power from the generator be adjustable
istics except frequency range. down to very low levels. Thus, the 61 4 A and
Both generators have three outstanding 61 6 A have been designed to provide outputs
characteristics that give them a high degree as low as 0.1 microvolt. This low level is
of usability: they are direct-reading in fre more than sufficient to test present receivers.
quency, direct-reading in output power, and The matter of high output from the gener
cover a wide frequency range. The very real ator is of secondary importance in receiver
value of these characteristics will be recog testing. A maximum generator output in the
nized at once by those who have worked order of a hundred microwatts is usually
with frequency charts and power output adequate. However, the general usefulness
curves for the once-common narrow-band
of a signal generator is greatly increased if
UHF generators.
higher output is available. For example, one
of the major uses for UHF generators with
higher output is as signal sources for slotted
line work. Several features of the 6l4A and
6l6A make these generators especially con
venient for slotted line work. For one thing,
the output of the generators is at least one
milliwatt (0.22 volt) over the complete
range of each generator. Although more
power is sometimes desired, an output of one
milliwatt is adequate for standing-wave
measurements when using the -hp- slotted
line sections and the Model 41 5 A Standing
Fig. 1. -hp- Model 616A UHF Signal Generator operates Wave Indicator. The 41 5 A has a full scale
from 1800 to 4000 megacycles with maximum output of
at least one milliwatt. Model 614A is similar in appear sensitivity of 0.3 microvolt which, in com
ance and circuitry but operates from
800 to 2100 megacycles. bination with a generator power level of
P R I N T E D I N U . S . A . C O P Y R I G H T 1 9 5 2 H E W L E T T - P A C K A R D C O .