A 110 microsecond positive pulse, of 12 volts amplitude,
Example: A close in, slow moving target will cause
is therefore applied to the gate of Q16 in synchronism
a high amplitude, low frequency signal.
with every positive-going transition of the square wave
A distant, fast moving target will cause a
low amplitude, high frequency signal.
When the square wave is at its higher level, the
Therefore, the charge rate of the tandem integrator is a
integrator capacitor, C31, charges through R42 until the
function of the target range and rate of movement.
Q13 base voltage is high enough to turn Q13 on. Due
to the integrator time-constant, Q13 is not fired until
When a high charge is accumulated on the
after Q14 has generated the 110 microsecond pulse.
tandem integrator, a 120 second interval is required to
When the square wave returns to the lower level, C31
fully discharge it.
discharges, and Q13 eventually turns off. The integrator
time-constant is such that this occurs prior to the next
The integrator output is amplified by linear
positive-going transition of the square wave, for Doppler
amplifier Z4 and its output is also the BALANCE test
frequencies expected from human targets.
point. The critical voltage level at this test point for
actuating the alarm is +0.8 or -0.8 volts.
During the time that Q13 is held on, the base of
Q14 is clamped to + 6 Vdc, eliminating the possibility of
Bipolar detector Q18 and Q19 detects the plus
Q14 firing during this interval. Q13 thus serves to
and minus voltage output of Z4 and the NOISE level
prevent random noise or other interference from causing
from peak limiter amplifier Z1 to trigger one shot
spurious, non-synchronized pulses to appear at the Q16
Multivibrator Q20 - Q21 and actuate alarm relay K1.
The one shot Multivibrator, when triggered, latches in for
approximately a 1 second interval for a momentary
The analog channel signal, from its Doppler
detected motion. It remains locked in for a continuously
bandpass filter, is processed by the logarithmic
detected motion and drops out several seconds after the
amplifier, Z3, resulting in an output signal where the
detected motion ceases. Alarm switch Q22 provides
amplitude is a logarithmic function of range, and the
approximately 12 Vdc at the ALARM test point when
period is determined by target velocity.
relay K1 is actuated. During normal operation and no
compression of this signal increases as target range
detected motion, relay K1 is in the energized state (no
alarm). Relay K1 is held in this state by dc power and
the signal from oscillator shaper Q5. Therefore, loss of
When a moving target is detected, the Z3 output
dc power or an oscillator failure will result in relay K1
signal is applied to the input of the synchronized
deenergizing thus signaling an alarm.
sampling gate, Q16. As the digital and analog channel
signals have a 90 degree phase difference, the 110
c. DC Voltage Regulation. Power for operating
microsecond gating pulse is always applied to Q16 in
the processor and the transceivers is provided by the J-
synchronism with either the positive or negative peak
SIIDS control unit in the form of +20 ± 2 Vdc which is
(depending on target direction) of the Z3 output signal.
regulated and dropped to a lower voltage. A block
For an approaching target, Q16 is gated in the negative
diagram of the power regulator is shown in figure FO-2,
peak; for a receding target, on the positive peak. The
located at rear of manual. Diode CR8 provides circuit
gated output signal from Q16 charges a tandem
protection against accidentally reversing the input power
integrator consisting of R52, C39, R53, C42, and C43.
polarity connections to the processor. Voltage regulator
Z5 regulates the input dc power at +12 Vdc which is
used throughout the processor as well as being applied
to a second series regulator (Q 7) which provides a +6
The amplitude output of Q16 is
inversely proportional to the range of
the detected moving target and the
frequency output is proportional to the
rate of movement.