A frequency control circuit including a control circuit for setting a set
value, an adding circuit for adding the set value per unit time and
effecting counting based on the adding result, and a signal output
circuit for outputting an alternating signal of a cycle corresponding to
the time necessary for the count result by the adding circuit to reach a
target value. The control circuit sets the set value as a value which
does not correspond to a submultiple of the target value, and the adding
circuit starts the counting of a next cycle when the count result reaches
the target value. The control circuit further sets an initial value of
the counting of the next cycle in accordance with a value of a portion of
the adding results, exceeding the target value when the count result
reaches the target value.