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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. 1
^^^^M
LISHED CALIFORNIA THE HEWLETT-PACKARD COMPANY, 275 PAGE MILL ROAD, PALO ALTO, CALIFORNIA SEPTEMBER, 1955
A New 3 CPS-100 KG Electronic Frequency Meter
with Discriminator Output and Expandable Scale
"T7LECTRONIC frequency meters, as distin- enables the instrument to be used as a wide
1 J guished from electronic frequency count band discriminator in applications where the
ers, are instruments that indicate the frequency measured signal contains very rapid frequency
of an applied waveform on a calibrated meter changes or frequency modulation. The dis
scale. The current that operates the indicating criminator voltage, when filtered, can be used
meter is also usually made available for operat in measuring the amount of deviation in the
ing an external d-c recorder. signal as well as the rate and components of the
Besides indicating an applied frequency and deviation.
providing a recorder output, however, the new Frequency-wise, the new instrument will di
-hp- Model 500B Electronic Frequency Meter rectly measure frequencies from 3 cps to 100 kc
is designed to be valuable in two other types of in nine ranges to a full scale accuracy of within
measurements. First, it is designed to be able to ±2%. The applied voltage can have nearly any
expand its scale readings by factors of 3 or 10 of the common waveforms. Random as well as
times, an arrangement that facilitates measure equally-spaced signals can be measured.
ments of frequency changes such as might be The instrument further provides a d-c supply
caused by line voltage changes on frequency- for operating the -hp- 5 06 A Optical Pickup, a
generating circuits. Second, the instrument is device that detects even the fastest rotary mo
designed to provide an output voltage which tions and supplies an appropriate signal to be
is proportional to the applied frequency. This measured by the frequency meter.
EXPANDABLE SCALE
The 3 or 10 times expandable scale feature
enables frequency changes to be measured with
increased accuracy. If the frequency shift en
countered in a 2 kc frequency were to be meas
ured, for example, 10 times expansion will
permit 10% of the meter scale placed in the
vicinity of 2 kc to occupy the entire meter
swing. In expanded operation the absolute
reading of the meter will not be indicative of
the applied frequency, but the calibrations of
the meter, in addition to being expanded or
magnified, are still direct-reading as far as the
differential frequency is concerned. Expanded
Fig. 1. Neu- -hp- Model 500B Electronic Frequency Meter operation is further facilitated by a panel con
measures frequencies from 10 cps full scale to 100 kc full
scale in 9 ranges. Special features include a discriminator trol that permits the meter pointer to be posi
output for measuring f-m and the ability to expand its scale
for increased accuracy in frequency change measurements. tioned to any arbitrary point on the meter scale
PRI NTED IN U.S.A. C O P Y R I G H T 1 9 5 5 H E W L E T T - P A C K A R D C O .