Functional Description
The relationships between the major circuit elements are shown in the block diagram opposite.
The summing amplifier sums the voltages from the dial and from the sweep input, and its output
controls the magnitude of the complementary current source and current sink. This current varies
from approximately 5.2uA to 5.2mA for a 1000:1 frequency change (.005-5.0).
The symmetry control adjusts the ratio between current source and current sink.
The diode gate steers current into or out of the range multiplier capacitor and is controlled by the
comparator output. When the comparator output is high the charge on the capacitor will rise,
linearly, producing the positive going triangle slope. When the comparator output is low the charge
on the capacitor will fall linearly producing the negative going triangle slope. The triangle amplifier
has unity gain and buffers the triangle wave on the multiplier capacitor to drive the comparator and
output circuits.
The comparator operates as a window detector with fixed limit points set to the triangle peaks. One
of its two outputs drives the TTL circuit and is also level shifted to drive the diode gate. The other
output drives the squarewave shaper. When the comparator output to the diode gate is high, the
triangle wave is positive going until this reaches approxi1.2V, the comparator output then
switches low. When the comparator output is low the triangle wave is negative going until this
reaches approximately -1.2V, when the comparator output goes high, and the cycle is repeated.
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