Digital frequency generator

A two-mode digital pulse generator producing a selectable frequency output determined by a controlling computer, said computer also selecting the mode of operation depending on the selected frequency comprising:

• a. storage means for receiving a multiple bit binary number in parallel from said computer;
• b. means for producing clock pulses;
• c. means for counting said clock pulses and producing a carry signal when counting capacity is exceeded including first and second counters each producing a carry signal when they overflow;
• the carry signal of the 1st counter incrementing the second counter;
• d. means tranferring said binary number into both of said counters in a first mode and a portion of said number into only the 1st counter in a second mode to preset the initial value at which counting begins;
• e. means responsive to the second counter carry signals in said first mode and to the first counter carry signals in said second mode for producing said output pulses at the selected frequency;
• f. comparison means operative in said second mode for repetitively comparing the value of the second counter against the untransferred protion of said binary number in said storage means to produce an inhibit output indicative of the need for counting inhibition to maintain the selected frequency output;
• g. logic means receiving said inhibit output, in the second mode, for inhibiting counting for a predetermined period to effect correction of the output pulse frequency.