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GENERAL DESCRIPTION
CIRCUIT DESCRIPTION
(1) WIEN BRIDGE OSCILLATOR
The wien bridge oscillator circuit elements consist of the capacitance elements.
which may be switched over for 5 range by the frequency range switch, excepted
programed 2 range (400Hz. 1KHz). and the variable resistor controlled by the
frequency variable.
The elements provide means to vary the oscillating frequency continuously over 1 0
times if frequency on one range, thus determining any desired frequency within the
entire frequency range from 1OHz to 1 MHz.
The amplifire circuit for the oscillator circuit is composed of a 2-stage differential
amplifier circuit. First stage is a high input impedance circuit with FET while the driver
stage is a wide band, high amplification type circuit with transistors featuring high
cut-off frequency.
The output stage is a S.E.P.P. circuit using complementary transistors.
The output voltage is fedback with positive polarity through the oscillator elements
to from an oscillating circuit, while it is also fedback with negative polarity though
the non-linear thermistor to stabilize the amplitude.
(2) SQUARE WAVE SHAPING CIRCUIT
The square wave shaping circuit is a schmidt trigger circuit in which the sinewave signal
from the oscillator circuit is shaped into a square wave. It is composed of an emittei
coupled schmidt trigger circuit and a buffer amplifier, thus providing sufficient rising and
falling characteristics.
(3) OUTPUT CIRCUIT
The output circuit converts the impedance of signal from the OUTPUT control and
feeds the signal to the output attenuator at a low impedance.
It is a S.E.P.P. O.C.L circuit employing complementary transistor to provide sufficiently
low output impedance characteristics over the range from DC to 1 MHz.
(4) OUTPUT A TTENUA TOR
The 4 position output attenuator selects attenuations of OdB to -70dB. At the OdB
position with the output amplitude VR control turned fully clockwise, the output
voltage(sinewave : open circuit) is more than 8Vrms
The output impedance is rated for 600Q or 50Q.
13
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