IBM 7220, Инструкция по эксплуатации

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4-3
Chapter 4, FRONT AND REAR PANELS
precision. In these cases a significant number of keypresses are required to make
adjustments.
Adjustment of the latter type of control is made easier by the use of one or other of
the two methods described below.
Auto Repeat
If an up or down ADJUST key is pressed and held, then its action is automatically
repeated such that the displayed control setting will increment or decrement at a rate
approximately ten times faster than that which could be achieved by repeated manual
keypresses.
Active Cursor
The ADJUST keys can be used initially to place a cursor over a given digit in the
displayed control setting, prior to changing that digit. This is done by using the
procedure discussed below.
Step 1 Press both the up and down ADJUST keys simultaneously. A cursor
appears over one of the displayed digits (see figures 4-5 and 4-6).
Step 2 With the cursor visible, repeating step 1 causes the cursor to move to the
left. When the cursor reaches the most significant digit available (left end of
control setting) the next keypress returns the cursor to the least significant
digit (right end of control setting). Continue this action until the cursor
covers the required digit.
Step 3 Press the up or down ADJUST key to change the digit to the required value.
Figure 4-5, Active Cursor Activation
As an example of this operation, suppose that the oscillator frequency is 50 kHz and
it is required to change it to 51 kHz. Simultaneously press both the up and down
ADJUST keys adjacent to the oscillator frequency display. Move the cursor, by
repeated double keypresses, until it is over the required digit, in this case the zero to
the right of the leading 5. Then press the up ADJUST key to increment the frequency
by 1 kHz. The cursor will disappear as soon as the frequency is adjusted but its
position remains active until changed (see figure 4-6).