repetition frequency and provide the synchronizing pulse for the
other components of the system. This may be done by a selfpulsing
or blocking oscillator with properly chosen circuit constants. This
method of timing eliminates a number of special timing circuits, but
the pulse repetition frequency obtained may be less rigidly
controlled than that desired for some applications.
The timing pulses required from a timer may depend largely
upon the purpose of the electronic equipment.
(1) Oscilloscope and television timing. Typical requirements
for oscilloscopes and televisions are illustrated in Figure 10. The
diagram does not necessarily apply to any particular oscilloscope or
television, but it shows the more common timing pulses that are in
general use. In Figure 11, these timing pulses are shown in their
proper time relationship.
Figure 10. Typical timing of an oscilloscope