Hybrid frequency synthesizer

• Main Authors: JUNG; YOUNG-JU, PARK; YOUNG-OK
• Format: Patent
• Language: English
• Published: 12.08.1997
• Edition: 6
• Subjects: AUTOMATIC CONTROL, STARTING, SYNCHRONISATION, OR STABILISATIONOF GENERATORS OF ELECTRONIC OSCILLATIONS OR PULSES; BASIC ELECTRONIC CIRCUITRY; ELECTRICITY; GENERATION OF NOISE BY SUCH CIRCUITS; GENERATION OF OSCILLATIONS, DIRECTLY OR BY FREQUENCY-CHANGING,BY CIRCUITS EMPLOYING ACTIVE ELEMENTS WHICH OPERATE IN ANON-SWITCHING MANNER

A hybrid frequency synthesizer combining a direct frequency synthesizer and a PLL synthesizer are disclosed. The direct frequency synthesizer includes a first and second phase accumulator, the second phase accumulator inputting K/N phase data and operating at M times faster than the first phase accumulator, a 360 degree detector adding the outputs of the first and second phase accumulators and detecting a point in time at which the added values become 360 degrees, which point in time is provided to the initialization circuit. The initialization circuit initializes the state of the first and second phase accumulators and controls the output timing of the first phase accumulator so as to synthesize the next period of the output frequency at the initialized time. Accordingly, the present invention simplifies the construction, and is economical.