PURPOSE: To supply a frequency with very high accuracy in a short time, by detecting and correcting the error of oscillating frequency at each sweep.
CONSTITUTION: An output frequency of a voltage controlled oscillator 1 is converted into a suitable low frequency at a frequency converter 12 with respect to an arbitrary frequency and inputted to a programmable counter 15 with gate circuit 14. The counter 15 counts the number of signal waves during the open time of the gate 14 and outputs the difference with a reference number. This difference is added with control voltage information to the present oscillation frequency stored in a memory 18 and temporarily stored to a latch circuit 17 as the oscillation frequency controlling voltage information at the next sweep. The memory is rewritten with the control voltage information after the correction and waits for the next sweep. The storage in a circuit 17 is coverted into an analog control voltage with a D/A converter 20 to control the oscillation frequency of the oscillator 1.
| WO/1996/023232 | SPECTRUM ANALYZER |
| JPS54138357 | SWEEP OSCILLATOR |
NAGANO KENJI
OKAMOTO SHIGEHARU
