CABLE-WRAP CIRCUITS

CE-1008

are used to set or reset a flip-flop, depending upon the direction of antenna rotation. When the output is from the ONE

side of the flip-flop, one side of a 6. 3-volt transformer winding is connected to ground. When the output is from the

ZERO side of the flip-flop, the other winding of the 6. 3-volt transformer is connected to ground. Thus, the voltage at the

center tap of the 6. 3-volt transformer will reverse phase when the flip-flop is alternately switched on and off. The

voltage from the 6. 3-volt transformer's center tap is AC-coupled by a capacitor C1 to SCAN CONTROL GAIN

potentiometer R3. The movable arm of R3 determines the amount of error voltage which is applied to the servoamplifier

and, subsequently, the rate at which the antenna scans the predetermined sector. The servoamplifier drives azimuth

drive motor MG1 which, in turn, through a gear train, drives the manual/scan control transmitter synchro B3, repositioning

the rotor of B3 so that a voltage appears on the stator leads. The system functioning from this point through

repositioning of the antenna is essentially the same as in the manual mode of operation. Drive motor MG1 also drives

potentiometer R4, through the gear train, in an increasing or decreasing direction depending upon the direction of

antenna rotation. When R4 is positioned such that it corresponds to the maximum sector to be scanned, either clockwise

or counterclockwise, the flip-flop in the scan generator is either set or reset, depending upon its previous condition, and

drives the antenna in the opposite direction. When SCAN CONTROL SECTOR width potentiometer R2 is rotated fully

counterclockwise, only a few degrees of movement of potentiometer R4 is required to set or reset the flip-flop. When the

potentiometer R2 is rotated clockwise, it requires proportionally larger angles of rotation of the potentiometer R4 to set or

reset the flip-flop. Therefore, with potentiometer R2 rotated full counterclockwise, the angle scanned will be small; that

is, approximately 10 degrees. With potentiometer R2 rotated full clockwise, the width of the angle scanned increases to

the full 270 degrees. The function of scan limit switch S8 is to deenergize the clutch when the scanned angle exceeds

270 degrees to avoid damaging the center positioning spring of potentiometer R4.

CABLE-WRAP CIRCUITS (See Figure 1-5) - The cable-wrap circuit consists of: potentiometer A3R1 in the

antenna pedestal which is ganged to the azimuth limit switch and geared to the azimuth drive assembly, meter M1, and

resistors R8, R15, R7, R14 and R16 in the Control Indicator. The function of this circuit is to indicate the limits of the

azimuth cable wrap in either a CW or CCW direction. The cable-wrap meter M1 is essentially a 0- to 50-millimeter with a

zero center-scale marking and red markings which indicate the limits of the cable wrap in either a CW or CCW direction

at either end. With the antenna positioned at 0 degree, the movable arm of A3R1 is positioned so that the current

through M1 is such that the meter is balanced (at zero center scale). As the antenna travels in a CW direction, the

current through meter M1 increases, causing the deflection of the meter to increase. As the antenna travels in a CCW

direction, the current through meter M1 decreases, causing the deflection of the meter to decrease. CABLE WRAP

indicator M1 will indicate the position of the antenna. The cable-wrap meter is adjusted by potentiometers R8 and R7 so

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Index