Frequency synthesizer for frequency hopping communication system

Claim 1

A frequency synthesizer, comprising: a phase detector having first and second inputs and an output; a loop filter connected to said output to produce a filtered signal; a voltage controlled oscillator (VCO) responsive to said filtered output for producing an output frequency; a programmable divider, having an adjustable divide ratio, receiving said output frequency and applying a divided frequency to said second input of said phase detector; a stable source of oscillations coupled to said first input of said phase detector; controller means for systematically adjusting the divide ratio of said programmable divider thereby selecting said output frequency from a group of N frequencies each separated from an adjacent frequency by a frequency spacing so that said output frequency alternates between: (a) increasing in steps of two times said frequency spacing so that alternating output frequencies are selected when said VCO output frequency is increasing thereby leaving frequencies adjacent said selected frequencies unselected; and (b) decreasing in steps of two times the frequency spacing so that said output frequencies adjacent said frequencies which were selected in part (a) are selected when said VCO output frequency is decreasing; and wherein said controller can consecutively select two adjacent channel frequencies at the uppermost or lowermost frequencies in order to make a transition (a) to (b) and (b) to (a).

Claim 6

A method of hopping output frequency in a device including a frequency source for generating a plurality of N output frequencies F(1) through F(N) where N is an even integer, F(1) is the lowest of said output frequencies and F(N) is the highest of said output frequencies and each of said N output frequencies F(J) is higher than the proceeding output frequency F(J-1), said method comprising the steps of: (a) setting said output frequency F(J) to F(1) for a predetermined time period; (b) increasing said output frequency by setting F(J)=the lesser of F(N) and F(J+2); (c) maintaining the frequency set in step (b) for said predetermined time period; (d) repeating steps (b) and (c) until F(J)=F(N); (e) decreasing said output frequency by setting F(J)=the greater of F(1) and F(J-2); (f) maintaining the frequency set in step (e) for said predetermined time period; and (g) repeating steps (e) and (f) until F(J)=F(1).

Claim 7

A method of hopping output frequency in a device including a frequency source for generating a plurality of N output frequencies F(1) through F(N) where N is an even integer, F(1) is the lowest of said output frequencies and F(N) is the highest of said output frequencies and each of said N output frequencies F(J) is higher than the proceeding output frequency F(J-1), said method comprising the steps of: (a) setting said output frequency F(J) to F(1) for a predetermined time period; (b) increasing said output frequency by setting F(J)=the lesser of F(N) and F(J+2); (c) maintaining the frequency set in step (b) for said predetermined time period; (d) repeating steps (b) and (c) until F(J)=F(N); (e) decreasing said output frequency by setting F(J)=the greater of F(1) and F(J-2); (f) maintaining the frequency set in step (e) for said predetermined time period; and (g) repeating steps (e) and (f) until F(J)=F(1).

Claim 12

A method of hopping output frequency in a device including a frequency source for generating a plurality of N output frequencies F(1) through F(N) where N is an odd integer, F(1) is the lowest of said output frequencies and F(N) is the highest of said output frequencies and each of said N output frequencies F(J) is higher than the proceeding output frequency F(J-1), said method comprising the steps of: (a) setting said output frequency F(J) to F(1) for a predetermined time period; (b) increasing said output frequency by setting F(J)=F(J+2); (c) maintaining the frequency set in step (b) for said predetermined time period; (d) repeating steps (b) and (c) until F(J)=F(N); (e) setting said output frequency to F(N-1) for said predetermined time period; (f) decreasing said output frequency by setting f(J)=the greater of F(1) and F(J-2); (g) maintaining the frequency set in step (f) for said predetermined time period; and (h) repeating steps (f) and (g) until F(J)=F(1).

Claim 13

A method of hopping output frequency in a device including a frequency source for generating a plurality of N output frequencies F(1) through F(N) where N is an odd integer, F(1) is the lowest of said output frequencies and F(N) is the highest of said output frequencies and each of said N output frequencies F(J) is higher than the proceeding output frequency F(J-1), said method comprising the steps of: (a) setting said output frequency F(J) to F(1) for a predetermined time period; (b) increasing said output frequency by setting F(J)=F(J+2); (c) maintaining the frequency set in step (b) for said predetermined time period; (d) repeating steps (b) and (c) until F(J)=F(N); (e) setting said output frequency to F(N-1) for said predetermined time period; (f) decreasing said output frequency by setting f(J)=the greater of F(1) and F(J-2); (g) maintaining the frequency set in step (f) for said predetermined time period; and (h) repeating steps (f) and (g) until F(J)=F(1).