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Frequency Divider

IP.com Disclosure Number: IPCOM000083205D
Original Publication Date: 1975-Apr-01
Included in the Prior Art Database: 2005-Mar-01
Document File: 2 page(s) / 26K

Publishing Venue

IBM

Related People

Monrolin, J: AUTHOR

Abstract

Shown is a divider to permit the frequency of a signal to be divided for deriving therefrom, a signal with a predetermined frequency and phase.

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Frequency Divider

Shown is a divider to permit the frequency of a signal to be divided for deriving therefrom, a signal with a predetermined frequency and phase.

A quartz oscillator 1 provides a signal having frequency fo to be divided. This signal is applied to two frequency dividers, a divider by p, 2, and a divider by q, 3. Output signals of dividers 2 and 3 may be expressed by cos {(2 pi fo/p) t = phi} and cos {(2 pi fo/q) t + phi'}, respectively.

Outputs of dividers 2 and 3 are connected to pi/phase phase 4 and 5, respectively the outputs of which provide signals sin {(2 pi fo/p) t + phi) and sin {(2 pi fo/q) t + phi'}, respectively.

The cosine signals are applied to multiplier circuit 6 and the sine signals are applied to multiplier circuit 7. Summing''subtracting circuit 8 receives the cosine products and the sine products from circuits 6 and 7 to produce, at the output of filter 9, a signal which may be expressed by cos {2 pi (fo/p +/- fo/q) t + (phi - phi')} depending upon the particular operation performed by circuit 8.

Thus, the divisor which is equal to (1/p +/- 1/q) and the phase of the output signal are controllable by varying p or q. In a divider by 10, p and q are chosen equal to 90 and 9 which improves the accuracy of the division.

To obtain a signal which may be expressed by sin {2 pi (fo/p +/- fo/q) t + phi - phi')}, the product of the inphase signal at the output of circuit 5 and the product of the quadrature signal at the output of circuit 4...