||The Model 200CD's wide frequency coverage made it very valuable as a general purpose oscillator.
An audio oscillator is an instrument that generates one pure tone
or frequency at a time. Through the years, HP oscillators were used
to design, produce and maintain telephones, stereos, radios and
other audio equipment.
The Model 200CD and its sister instrument, the Model 200AB, were
introduced at the same time in 1952. These new oscillators represented
a substantial increase in versatility over previous ones. For example,
the frequency range of the 200CD (5 cps to 600 kc) was such that
it replaced two of the older HP oscillators, Models 200C and 200D,
which were discontinued. This was accomplished without an increase
in price. The wide frequency coverage made this instrument very
valuable as a general purpose oscillator.
In addition to advances in electrical design, the cabinetry of the
new oscillator was redesigned. The cabinet width was reduced to
save bench space, while the appearance was designed to be more pleasing
and to aid in operation. One of the improvements was a large, 6-inch
The 200CD was used for testing servo and vibration systems, medical
and geophysical equipment, audio amplifiers, sonar and supersonic
apparatus, carrier telephone systems and video frequency circuits.