Modulation synthesis method and apparatus

Claim 3

A method as claimed in claim 1 wherein the modification of the carrier wave is carried out by gating the carrier wave on and off for periods determined by the sample point values to thereby establish a pulse duration modulated carrier signal.

Claim 4

A method as claimed in claim 2 wherein the carrier wave is gated on for a period proportional to each sample point value to thereby establish the pulse duration modulated carrier signal.

Claim 5

A method as claimed in claim 2 wherein the carrier wave is gated off for a period proportional to each sample point value to thereby establish the pulse duration modulated carrier signal.

Claim 6

A method as claimed in claim 1 wherein the modification of the carrier wave is carried out by varying the attenuation of the carrier wave by amounts determined by the sample point values to thereby establish an amplitude modulated carrier signal.

Claim 7

A method as claimed in claim 1 wherein the modification of the carrier wave is carried out by varying the delay of the carrier wave by amounts determined by the sample point values to thereby establish a phase modulated carrier signal.

Claim 8

A method as claimed in claim 1 including the additional step of modifying the sample point values during transfer to insert additional signal information therein prior to application of those point values to modify the carrier signals.

Claim 9

A method as claimed in claim 7 wherein the modification is carried out by multiplying each sample point value by a scale factor.

Claim 10

A method as claimed in claim 7 wherein the modification of the sample point values consists of storing and reading out a second plurality of different sample point values in step with the reading out of the first mentioned plurality of sample point values, and modifying the first mentioned plurality of sample point values by combining corresponding individual point values of the second plurality of sample point values with the individual point values of the first mentioned plurality of sample point values to provide combined sample point values.

Claim 11

A method as claimed in claim 9 wherein the combination of individual members of the first plurality of sample point values with the individual members of the second plurality of sample point values is carried out by an arithmetic addition of the point values.

Claim 12

A method as claimed in claim 10 wherein the modification is carried out by multiplying each member of said first mentioned plurality of sample point values by a first scale factor, and multiPlying the corresponding member of the second plurality of sample point values by a second scale factor which is a complement of said first scale factor before addition of each pair of individual members of said first and second plurality of sample point values.

Claim 13

A method as claimed in claim 11 wherein said first plurality of sample point values and said second plurality of sample point values respectively represent signal wave frequencies having a common period of repetition, and wherein said first plurality of sample point values and said second plurality of sample point values are read out in sequence over the entire common period of repetition, and then the operation is repeated to provide continuous modulation at the frequencies represented by said first and second pluralities of sample point values.

Claim 14

Apparatus for synthesizing the production of a modulated radio carrier wave comprising storage means for continuously storing the same group of digital values corresponding to a plurality of different sample points signifying various modulation levels required at successive points in time to suggest the presence of a modulation signal wave form, means for reading out said sample point values in timed sequence, a source of carrier waves, means for transferring and means for applying said point values to modify the carrier waves to produce a modified carrier which is recognizable by a receiver as a carrier modulated by a repetitive wave form modulation signal.

Claim 15

Apparatus for synthesizing the production of a modulated radio carrier wave comprising storage means for continuously storing the same group of digital values corresponding to a plurality of different sample points signifying various modulation levels required at successive points in time to suggest the presence of a modulation signal wave form, means for reading out said sample point values in timed sequence, a source of carrier waves, means for transferring and means for applying said point values to modify the carrier waves to produce a modified carrier which is recognizable by a receiver as a carrier modulated by a repetitive wave form modulation signal.

Claim 16

Apparatus as claimed in claim 13 wherein said means for applying said point values to modify the carrier wave comprises a gating device operable to gate the carrier on and off for periods proportional to the sample point values to thereby establish a pulse duration modulated carrier signal.

Claim 17

Apparatus as claimed in claim 13 wherein said means for transferring said point values includes means for modifying the sample point values to insert additional signal information therein prior to application to said carrier wave modifying means.

Claim 18

Apparatus as claimed in claim 15 wherein said sample point value modification means comprises means for storing and reading out a second plurality of different sample point values in step with the reading out of the first mentioned plurality of sample point values, and means for combining individual point values of the second plurality of sample point values with the individual point values of the first mentioned plurality of sample point values to provide the combined sample point values.

Claim 19

Apparatus as claimed in claim 15 wherein said modifying means comprises means for multiplying each sample point value by a scale factor.

Claim 20

Apparatus as claimed in claim 16 wherein said combining means comprises an adder.

Claim 21

Apparatus as claimed in claim 18 wherein said modifying means includes at least one multiplier for multiplying each member of said first mentioned plurality of sample point values by a first scale factor and for multiplying the corresponding member of the second plurality of sample point values by a second scale factor which is a complement of said first scale factor before addition of each pair of individual members of said first and second plurality of sample point values.

Claim 22

Apparatus as claimed in claim 14 including at least one register-counter means for storing each sample point value after it is read out of said storage means, said register-counter means being operable to count down to zero over a period determined by the digital sample point value stored therein commencing with a clock signal, said register-counter means being connected to control said gating device to provide a first gating state during the counting down operation of said register-counter means and to provide a second gating state after the counting down operation has been completed to thereby gate the carrier on and off.

Claim 23

Apparatus as claimed iN claim 20 wherein said first gating state of said gating device is on and said second gating state of said gating device is off.

Claim 24

Apparatus as claimed in claim 20 wherein said first gating state of said gating device is off and said second gating state of said gating device is on.

Claim 25

A method as claimed in claim 1 wherein a predetermined fixed minimum value is employed with all of said plurality of different sample point values to thereby fix a minimum value modulated level for the modified carrier.