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HEWLETT-PACKARD
JOURNAL
TECHNICAL INFORMATION FROM THE -dp- LABORATORIES Vol. 8, No. 8
H.ISHED BY THE HEWLETT-PACKARD COMPANY, 275 PAGE MILL ROAD, PALO ALTO, CALIFORNIA APRIL, 1957
A 250 CPS-100 KG Oscillator
For High Stability Applications
THE general family of -hp- audio oscilla will be seen that during this time the output
tors has always been known for stability, frequency remained within a band about 5
but included in this family is one oscillator cps in width. The instrument was operating
to which extra measures have been applied from an unregulated power line which did,
to obtain added stability for specialized work however, remain within a few volts of its
such as telemetry. This instrument is rated average value.
as being stable with At other frequencies within the instru
SEE ALSO:
How 200F stability was in 20 cps per hour at ment's range the percentage stability is often
plotted automatically, p. 3
Increased low-frequency 1 00 kc after warmup even higher. Fig. 3, for example, shows the
accuracy for counters, p. 4
and, of course, is gen stability at 10 kc. Note that the scale has been
erally noticeably better in a typical case. As changed in this curve and that the frequency
a result, the instrument is especially suited remained within a band only 0.2 cps or
to high-selectivity work such as checking 0.002% in width.
the response of narrow-band filters and test The key to the use of the Model 200T is
ing selective amplifiers. provided by the curve shown in Fig. 4. This
Fig. 2 shows a typical stability character is a typical warmup characteristic for the
istic for the instrument when operating at instrument when operating at 100 kc at
its highest frequency of 1 00 kc at room tem room temperature. In the first hour of warm-
perature after warmup. This curve encom up the output frequency changed about 118
passes a half-hour's operating time and it cps or 0.12%, but about 80 cps or 0.08% of
100,060 CPS
100,070 CPS
Fig. 2 (above). Typical stability characteristic of -hp-
Model 200T operating at its highest rated frequency of
100 kc after warmup. Even higher percentage stability
will usually be obtained at other output frequencies (see
fig. 3).
Fig. 1 (at left), -hp- Model 200T 250 cps-lOOkc oscil
lator is especially convenient for high-resolution work
such as encountered in telemetering field. Instrument has
high stability of output frequency, low sensitivity to line
voltage changes, and high resolution tuning system.
P R I N T E D I N U . S . A . C O P Y R I G H T 1 9 5 7 H E W L E T T - P A C K A R D C O .