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4.1.4
4.1.5
37
Sine shaper
The triangular oscillator voltage is shaped to :sinusoidal wave form by the sine shaper IC 0Q011.
Trimpots 808 and 812 serve for minimizing the output signal distortion.
The output
LRC-low pass
filter improves the signal shape at the upper frequency end of the oscillator. By trimpot 814 the am-
plitude response is adjusted. The sine wave is outputted by the isolation amplifier comprising transistors
350 and 351 and d.c. offset trimpot 816.
Amplifier, attenuator
One of the internally generated signals are selected by the wave form switches 252/5/6/7 and routed to
the amplitude potmeter
821. The following inverting amplifier basically consists of a complementary
high gain cascode
stage including the transistors 352 - 354 and a buffered complementary
emitter
follower output stage. Overall voltage gain mainly is defined by the ratio of feedback resistor 831 to
input resistor 820. Feedback trimmer
556 determines the square wave shape and the amplitude res-
ponse flatness at the upper frequency end. Trimpot 824 serves for zero offset adjustment, when the
DC OFFSET potentiometer 822 is switched off.
The output attenuator comprisesthree
resistor dividers by-passed or switched
on in any combination
through switches 252/9/10/11.
Power supply
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