C4
TM 9-4935-481-14-1
NOTE
(a) Amplitude of the sum and difference signals is measured by a peak detector designed specifically for
that purpose, as opposed to the general usage, lowfrequency peak detector controlled by another section of the DMS-D
Manual first pulse timing is fixed at 708 msec.
panel. The inherent offset voltage of the peak detector circuit may be nulled prior to use, and this is accomplished by the
align 1 potentiometer. The peak detector dc output is displayed on the DMM via position E8 of selector A, and the internal
test switch is set to position 5 to ground the input of the circuit. The align 1 potentiometer is then adjusted to obtain a null
reading on the DMM, thereby minimizing the errors involved in reading low-level sum or difference signals.
(b) All fixed automatic amplitudes of the sum and difference signals are derived from a reference
oscillator, whose amplitude must be calibrated prior to use due to long-term instability. This reference is nominally 10. 294
VP, but the actual calibration is performed by reading the sum signal automatic 3 AGC level and adjusting the align 2
potentiometer (which changes the reference) until the peak detector output is +9. 700 Vdc. This method of calibration
allows the greatest accuracy, since the DMM is reading at the high end of its lOV range, while if the reference itself were
being read, the DMM would be reading at the low end of its 100V range.
(c) The sum and difference potentiometers are used to set the amplitude of the respective signals when
enabled by the manual position of the sequence switch. Since the levels involved during automatic testing of the TTS are of
either a "filter" or "AGC" nature, the manual mode also corresponds to this shift in amplitude. After application of test start,
and prior to 16. 02 seconds, the adjustment range of either the sum or difference potentiometers will correspond to the filter
mode and be approximately 226 mVP to 509 mVP. At 16. 02 seconds, a scale factor change takes place, and the
adjustment range becomes approximately 3. 167 VP to 10. 8 VP to correspond to the AGC high level mode. The manual
The vertical wire simulator amptd (volts) potentiometer may then be used to adjust the pulse amplitude to +7. 500 Vdc, as
amplitude of either the sum or difference signal may be read by the peak detector described in (a) above. The internal test
observed on the DMM. When the function test switch is set to a position other than pulse read and the test start switch
switch must be set to position 3 to read sum, or position 4 to read-difference, and then the amplitude adjusted while
actuated again, the vertical wire signal will then be a pulse train with an amplitude of +7.500 Vdc.
observing selector A E8 on the DMM. Since the scale factor change occurs automatically at 16. 02 seconds, it would be
advisable to stop the clock prior to this time (by using the counter inhibit function) when setting a filter test level.
6.
To provide as much flexibility as possible when troubleshooting the TTS, a TTS counter
inhibit only position was included on the function test switch. With the TTS connected, the DMS-D would normally be
(3) Horizontal wire simulator. The manual horizontal wire simulator controls, dc level (R13) and ripple (R12),
operating with the TTS clock as a time base, but switching to the TTS counter inhibit only position would transfer DMS-D
provide a means of independently adjusting the two components of the horizontal wire signal.
timing control to the internal clock. Inputs are also fed to the counter inhibit logic so that time sequencing of the TTS may be
stopped, but the DMS-D sequencing would continue as in normal operation.
(a) Operation of the TTS is normally in either the boresight or missile command mode, and the range of
adjustment of the dc level control is dependent upon which of these two modes has been selected. The boresight mode
(2) Sum/difference simulator. The sum/difference simulator section contains sum potentiometer Rll, difference
(which can be simulated by internal test position 4) allows a range of approximately -630 mVdc to +630 mVdc when the pot is
potentiometer R1O, and align 1 and 2 potentiometers R14 and R18, respectively. These controls are used for amplitude
adjusted from fully ccw to fully cw, respectively.
adjustment of the manual sum and difference signals, and calibration of the simulator as described below.
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