Sect. I Page 1
SECTION I
GENERAL DESCRIPTION
1-1 INTRODUCTION as wave-form purity, constant output over a
wide range, stability, calibration accuracy,
The Model 207A Audio Sweep Oscillator cov- and other important features shown in the
ers the entire 20-cps to 20-kc frequency range TABLE OF SPECIFICATIONS.
ina single dial sweep. A synthesized RC net-
work enables the oscillator to be tuned over a The Model 207A is ehsy to operate: frequency
1OOO:l frequency range without bandswitching, and amplitude of the output signal are set
thus the entire audio range may be swept by a merely by operating dials on the control panel.
singla dial twist. This fpatur- makos th* 207A The easily read, six-inch diameter frequency
av-ry uspful test instrua1-nt inapplications in- dial is calibrated over 300' of arc.
volving response measurements of amplifiers,
transformers, speakers, and many other au- Usefulness of the oscillator has been extended
dio devices. by designing the 207A output circuit so that it
can be operated balanced as well as unbal-
The dial calibration of the Model 207A is es- anced. The oscillator output provides a ma=
sentially logarithmic. This characteristic imum of 20volts open circuit or 10 volts into
permits accurate presentation of waveforms a 600-ohm load at any frequency between 20
on an oscilloscope or recorder when making cps and 20 kc. A bridged-T variable attenua-
response measurements. To facilitate such tor in the output circuit controls the output
measurements, the 207A is arranged so that voltage level over a 40-db range.
an extension of the tuning dial shaft is avail-
able at the rear of the instrument. The shaft
extension may be equipped with an accessory 1-2 INSPECTION
potentiometer which, when used with a suit-
able d-c supply, provides alinear sweepvolt- This instrument was thoroughly tested and in-
age for use in observing response character- spected before being shipped, and is ready to
istics of audio devices. The shaft extension use when received.
may also be equipped with a reversing-motor
drive which permits automatic response meas- After the instrument is unpacked, it should be
urements to be made. inspected carefully for any damage it may have
received in transit. If any shipping damage
In addition to the above features the Model is found, follow the procedure outlined in the
207A retains all the basic advantages com- "Claim for Damage in Shipment" section at
mon to the -hp- line of RC-oscillators, such the back of this instruction book. |
ACEC
