05224132 is referenced by 29 patents and cites 21 patents.

A fractional divider using a counter means to provide fractionality. A divider is used to divide the VCO output signal by N or N+1 as selected. A divider control circuit controls the divider to divide by the appropriate divisor to obtain the selected output frequency. The fractional divider circuit counts divider control signals which represent a first division period. The fractional divider circuit establishes a second period of multiple first periods and at the terminal count of each second period, provides a selected number of fractional control signals to the divider control to cause division by a different number, such as N+1. The fractional divider comprises a first counter programmed to count first periods and issue its terminal count upon receiving the programmed count of first periods. The fractional divider also comprises a second counter to provide the selected number of fractional control signals upon receipt of the terminal count of the first counter. The first and second counters thus operate as a fraction, e.g. F/K, to result in a fractional reference frequency.

Title
Programmable fractional-N frequency synthesizer
Application Number
7/823286
Publication Number
5224132
Application Date
January 17, 1992
Publication Date
June 29, 1993
Inventor
Bar Giora Goldberg
San Diego
CA, US
Agent
Fulwider Patton Lee & Utecht
Assignee
Sciteq Electronics
CA, US
IPC
H03K 5/00
View Original Source