A-scope Display :

• This is the most popular type of the deflection modulation type display system which indicates the range of the target.
• The A-scope display, shown in figure, presents only the range to the target and the relative strength of the echo.
• The A-scope normally uses an electrostatic-deflection crt. The sweep is produced by applying a sawtooth voltage to the horizontal deflection plates. The electrical length (time duration) of the sawtooth voltage determines the total amount of range displayed on the CRT screen.
• The ranges of individual targets on an A-scope are usually determined by using a movable range gate or step that is superimposed on the sweep.

• In addition to this there are various signals displayed on the screen corresponding to:

  1) Ground clutter i.e. echoes from various fixed objects near the transmitter & from the ground.

  2) Grass noise i.e. an almost constant amplitude & continuous receiver noise.

  3) Actual targets. These signals are usually large.

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