Method and apparatus for peak-to-average ratio control in an amplitude modulation paging transmitter

Claim 1

A method for reducing the peak-to-average power ratio of a plurality of amplitude modulated voice signals for broadcast by a paging transmitter, the method comprising the steps of: (a) calculating an associated first gain sequence for each of said plurality of voice signals, said associated first gain sequence dependent upon the corresponding voice signal; (b) for each of said plurality of voice signals, multiplying the voice signal with said associated first gain sequence to provide a first compressed voice signal; (c) modulating at least one pair of said first compressed voice signal to produce at least one independent single sideband signal; (d) calculating a second gain sequence for each of said at least independent single sideband signals; (e) multiplying said second gain sequence with said independent single sideband signal to form at least one second compressed voice signal; and (f) multiplying each of said second compressed voice signals with an assigned predetermined carrier frequency to provide an output signal for broadcast.

Claim 2

A method for reducing the peak-to-average power ratio of a plurality of amplitude modulated voice signals for broadcast by a paging transmitter, the method comprising the steps of: (a) calculating an associated first gain sequence for each of said plurality of voice signals, said associated first gain sequence dependent upon the corresponding voice signal; (b) for each of said plurality of voice signals, multiplying the voice signal with said associated first gain sequence to provide a first compressed voice signal; (c) modulating at least one pair of said first compressed voice signal to produce at least one independent single sideband signal; (d) calculating a second gain sequence for each of said at least independent single sideband signals; (e) multiplying said second gain sequence with said independent single sideband signal to form at least one second compressed voice signal; and (f) multiplying each of said second compressed voice signals with an assigned predetermined carrier frequency to provide an output signal for broadcast.

Claim 10

A method for reducing the peak-to-average power ratio of an amplitude modulated voice signal for broadcast by a paging transmitter, the method comprising the steps of: (a) calculating a gain sequence for said voice signal, said gain sequence dependent upon said voice signal, said gain sequence calculated by: (i) calculating a first constant (c 1 ) based upon a predetermined sampling frequency and a first predetermined time constant; (ii) calculating a second constant (c 2 ) based upon said predetermined sampling frequency and a second predetermined time constant; (iii) calculating a filter response signal based as: a(n)=c.sub.1 a(n-1)+(1-c.sub.1)m(n) where n is an integer and m(n) is a metric of said voice signal; (iv) calculating an intermediate function as: p(n)=a(n) if a(n)>p(n-1) p(n)=c.sub.2 p(n-1) if a(n)≦p(n-1); and (v) calculating the gain sequence as: g(n)=MAXLEVEL/p(n), where MAXLEVEL is a predetermined constant, and (b) multiplying said voice signal with said gain sequence to provide a compressed voice signal.

Claim 11

A method for reducing the peak-to-average power ratio of an amplitude modulated voice signal for broadcast by a paging transmitter, the method comprising the steps of: (a) calculating a gain sequence for said voice signal, said gain sequence dependent upon said voice signal, said gain sequence calculated by: (i) calculating a first constant (c 1 ) based upon a predetermined sampling frequency and a first predetermined time constant; (ii) calculating a second constant (c 2 ) based upon said predetermined sampling frequency and a second predetermined time constant; (iii) calculating a filter response signal based as: a(n)=c.sub.1 a(n-1)+(1-c.sub.1)m(n) where n is an integer and m(n) is a metric of said voice signal; (iv) calculating an intermediate function as: p(n)=a(n) if a(n)>p(n-1) p(n)=c.sub.2 p(n-1) if a(n)≦p(n-1); and (v) calculating the gain sequence as: g(n)=MAXLEVEL/p(n), where MAXLEVEL is a predetermined constant, and (b) multiplying said voice signal with said gain sequence to provide a compressed voice signal.

Claim 13

A method for reducing the peak-to-average power ratio of a plurality of amplitude modulated voice messages broadcast by a paging transmitter, said amplitude modulated voice messages frequency multiplexed onto a plurality of subchannels, each subchannel including a lower sideband and an upper sideband, the method comprising the steps of: (a) generating a plurality of input digital sequences, each of said input digital sequences representative of a voice message to be broadcast by said paging transmitter; (b) providing each of said plurality of input digital sequences to a corresponding control gain generator, said corresponding control gain generator outputting a first digital gain sequence; (c) multiplying each of said input digital sequences with said first digital gain sequence from said corresponding control gain generator to form a first compressed digital sequence; (d) providing pairs of said first compressed digital sequences to a corresponding double single sideband modulator, said corresponding modulator outputting a modulated digital sequence comprising of an independent lower sideband and an independent upper sideband; (e) providing said modulated digital sequence to a second control gain generator, said second control gain generator outputting a second digital gain sequence; (f) multiplying said modulated digital sequence with said second digital gain sequence from said corresponding second control gain generator to form a second compressed digital sequence; (g) mixing said second compressed digital sequence with a carrier frequency to form a digital transmission signal; and (h) summing said digital transmission signal to achieve frequency multiplexing of said subchannels.

Claim 14

A method for reducing the peak-to-average power ratio of a plurality of amplitude modulated voice messages broadcast by a paging transmitter, said amplitude modulated voice messages frequency multiplexed onto a plurality of subchannels, each subchannel including a lower sideband and an upper sideband, the method comprising the steps of: (a) generating a plurality of input digital sequences, each of said input digital sequences representative of a voice message to be broadcast by said paging transmitter; (b) providing each of said plurality of input digital sequences to a corresponding control gain generator, said corresponding control gain generator outputting a first digital gain sequence; (c) multiplying each of said input digital sequences with said first digital gain sequence from said corresponding control gain generator to form a first compressed digital sequence; (d) providing pairs of said first compressed digital sequences to a corresponding double single sideband modulator, said corresponding modulator outputting a modulated digital sequence comprising of an independent lower sideband and an independent upper sideband; (e) providing said modulated digital sequence to a second control gain generator, said second control gain generator outputting a second digital gain sequence; (f) multiplying said modulated digital sequence with said second digital gain sequence from said corresponding second control gain generator to form a second compressed digital sequence; (g) mixing said second compressed digital sequence with a carrier frequency to form a digital transmission signal; and (h) summing said digital transmission signal to achieve frequency multiplexing of said subchannels.

Claim 16

An apparatus for reducing the peak-to-average power ratio of a plurality of amplitude modulated voice signals for broadcast by a paging transmitter, the apparatus comprising: (a) a first control gain generator for calculating an associated first gain sequence for each of said plurality of voice signals, said associated first gain sequence dependent upon the corresponding voice signal; (b) a plurality of first multipliers each associated with each of said voice signals, each of said multipliers multiplying its associated voice signal with said associated first gain sequence to provide a first compressed voice signal from each of said plurality of first multipliers; (c) at least one modulator for modulating pairs of said first compressed voice signal to produce at least one independent single sideband signal; (d) a second control gain generator for calculating a second gain sequence for each of said at least one independent single sideband signals; (e) at least one second multiplier for multiplying said second gain sequence with said independent single sideband signal to form at least one second compressed voice signal; and (f) at least one third multiplier for multiplying each of said at least one second compressed voice signals with an assigned predetermined carrier frequency to provide an output signal for broadcast.

Claim 17

An apparatus for reducing the peak-to-average power ratio of a plurality of amplitude modulated voice signals for broadcast by a paging transmitter, the apparatus comprising: (a) a first control gain generator for calculating an associated first gain sequence for each of said plurality of voice signals, said associated first gain sequence dependent upon the corresponding voice signal; (b) a plurality of first multipliers each associated with each of said voice signals, each of said multipliers multiplying its associated voice signal with said associated first gain sequence to provide a first compressed voice signal from each of said plurality of first multipliers; (c) at least one modulator for modulating pairs of said first compressed voice signal to produce at least one independent single sideband signal; (d) a second control gain generator for calculating a second gain sequence for each of said at least one independent single sideband signals; (e) at least one second multiplier for multiplying said second gain sequence with said independent single sideband signal to form at least one second compressed voice signal; and (f) at least one third multiplier for multiplying each of said at least one second compressed voice signals with an assigned predetermined carrier frequency to provide an output signal for broadcast.