Phase shift keyed transmission of dibits encoded to eliminate receiver phase uncertainty

Claim 3

A method according to claim 1, wherein n 2 and transmission is effected by quaternary phase modulation, in which information comprising a first binary sequence containing unlike signal steps, is transmitted by a first predetermined phase shift, a second binary sequence containing like signal steps of one binary state, are transmitted by a second predetermined phase shift, a third binary sequence, containing like signal steps of the other binary state, is transmitted by a third predetermined phase shift, and signal steps, occurring singly between two such successive binary sequences are transmitted as a continuation of the immediately preceding phase position.

Claim 4

A method according to claim 2, wherein information comprising the binary sequence of 01 is transmitted by a phase shift of 90* in one direction, information comprising the binary sequence 00 by a phase shift of 90* in the opposite direction and information comprising the binary sequence 11 by a phase shift of 180*, while the binary step 1 occurring only singly between two successive binary sequences is transmitted as a continuation of the immediately preceding phase position.

Claim 5

A method according to claim 1, wherein n 3 and transmission is effected by senary phase modulation, in which information comprising a first binary sequence, containing two like signal steps of one binary state followed by one signal step of the other binary state, is transmitted by a first predetermined phase shift, a second binary sequence, containing one signal step of one binary state followed by two signal steps of the other binary state, is transmitted by a second predetermined phase shift, a third binary sequence, containing two like signal steps of one binary state separated by a signal step of the other binary state, is transmitted by a third predetermined phase shift, a fourth binary sequence, containing like signal elements of one binary state, is transmitted by a fourth predetermined phase shift, a fifth binary sequence, containing like signal elements of the other binary state is transmitted by a fifth predetermined phase shift, and signal steps occurring singly or doubly between two successive binary sequences are transmitted as a continuation of the immediately preceding phase position.

Claim 6

A method according to claim 4, in which information comprising the binary sequences of 011 and 010 are transmitted by respective phase shifts of +60* and -60*, information comprising the binary sequences 001 and 000 are transmitted by respective phase shifts of +120* and -120*, and information comprising the binary sequence 111 by a phase shift of 180*, while the binary step 1 and the binary sequence 11 occurring between successive sequences of said first mentioned binary sequences are transmitted as a continuation of the immediately preceding phase shift position.

Claim 7

A circuit arrangement for transmitting a binary information signal comprising sequential digital signal steps in the form of binary states 0 or 1, one of which signal states represents a steady modulation condition of the binary information signal, by multistage phase modulation in groups of n signal steps, n being an integer greater than 1, comprising a carrier frequency generator, which is operative to provide the carrier oscillation in a plurality of different phase shift positions, preferably uniformly spaced with respect to one another, evaluation means responsive to the signal steps and having an input for receiving timing pulses at the same frequency as that of the signal steps, said evaluation means comprising a first counter constructed to count n number of steps, in which the first step is of one binary state, a second counter constructed to count n number of steps in which the first step is of the other binary state, and a forward-backward counter having 2n number of stages operatively connected and responsive to said first and second counters, said arrangement having an output from which phase-modulated signals are to be transmitted, and control means connected to said forward-backward counter for each phase position for operatively connecting the desired phase of the carrier frequency generator to said output and respectively responsive to different groups of binary states, as determined in said forward-backward counter, said carrier frequency generator providing 2n-1 phase shift positions for the transmission of the binary information signal, and an additional phase shift position for the transmission of n steps of the steady modulation condition of the binary information signal, no signal being passed from said first two counters in the presence of any signal steps of the binary state representing such steady modulation condition, which number less than n, separating two successive groups, whereby the immediately preceding phase shift position, 0* phase position, is retained.

Claim 8

A circuit arrangement for transmitting a binary information signal comprising sequential digital signal steps in the form of binary states 0 or 1, one of which signal states represents a steady modulation condition of the binary information signal, by multistage phase modulation in groups of n signal steps, n being an integer greater than 1, comprising a carrier frequency generator, which is operative to provide the carrier oscillation in a plurality of different phase shift positions, preferably uniformly spaced with respect to one another, evaluation means responsive to the signal steps and having an input for receiving timing pulses at the same frequency as that of the signal steps, said evaluation means comprising a first counter constructed to count n number of steps, in which the first step is of one binary state, a second counter constructed to count n number of steps in which the first step is of the other binary state, and a forward-backward counter having 2n number of stages operatively connected and responsive to said first and second counters, said arrangement having an output from which phase-modulated signals are to be transmitted, and control means connected to said forward-backward counter for each phase position for operatively connecting the desired phase of the carrier frequency generator to said output and respectively responsive to different groups of binary states, as determined in said forward-backward counter, said carrier frequency generator providing 2n-1 phase shift positions for the transmission of the binary information signal, and an additional phase shift position for the transmission of n steps of the steady modulation condition of the binary information signal, no signal being passed from said first two counters in the presence of any signal steps of the binary state representing such steady modulation condition, which number less than n, separating two successive groups, whereby the immediately preceding phase shift position, 0* phase position, is retained.

Claim 9

A circuit arrangement according to claim 6, wherein n 2, and said carrier frequency generator is operated to provide four different phase shift positions, said first and second counters each being constructed to count two signal steps, with one such counter being operable to count like steps of one binary state, operative to actuate said forward-backward counter to effect a predetermined phase shift, the other of such counters being operable to count groups beginning with a step of the other binary state, followed by a step of either binary state, operative to actuate said forward-backward counter to effect respective different phase shifts, signal steps of said one binary state occurring only singly between two successive groups being inoperative to effect actuation of said forward-backward counter whereby no phase shift, a 0* phase position, is effected thereby.

Claim 10

A circuit arrangement according to claim 7, wherein said carrier frequency generator is operative to provide four different phase shift positions, spaced by 90*, said control means being so constructed that a group comprising unlike signal steps is operative to effect a phase shift of 90* in one direction, a group comprising like signal steps of one binary state is operative to effect a phase shift of 90* in the opposite direction, and a group comprising like signal steps of the other binary state is operative to effect a phase shift of 180*.

Claim 11

A circuit arrangement according to claim 8, wherein said control means is so constructed that a group comprising signal steps of 01 is operative to effect a phase shift of +90*, a group comprising signal steps of 00 is operative to effect a phase shift of -90*, a group comprising signal steps of 11 is operative to effect a phase shift of 180*, and a signal step of 1 occurring only singly between said two successive groups is operative to effect no phase shift, 0* phase position.

Claim 12

A circuit arrangement according to claim 8, wherein each of said first and second counters comprises a bistable flip-flop stage, each bistable flip-flop stage being capable of being controlled in two stable positions respectively designated rest position and a working position, each bistable flip-flop stage having a timing input and being switched over between the two stable positions through timing pulses, applied to the timing input thereof, which occur at the step center of the binary information steps to be transmitted so that each of said bistable flip-flop stages operates as a frequency divider with a divider relation of 2:1, the switchover of one stage from the rest position Into the working position being possible only in the case of a 0 first step of the binary information signals to be transmitted, and the switchover of the other stage from the rest position into the working position being possible only in the case of a 1 first step of the binary information signals to be transmitted, said forward-backward counter comprising two bistable flip-flop stages and cooperable gate circuits which are connected in a ring, said counter having four counting positions and each counting position having an output line connected with respective control means operative to effect a connection of a corresponding phase position, 0*, 90*, 180* or 270*, of the carrier frequency generator, the forward-backward counter having its input connected to the bistable flip-flop stage of one of said two other counters whereby the forward-backward counter is actuated, in accordance with the particular binary state of the steps involved to effect a phase shift of 90* in forward or backward direction, and the bistable flip-flop stage of the remaining of said other two counters is operative to effect said phase shift of 180*.

Claim 13

A circuit arrangement according to claim 6, wherein n 3, and said carrier frequency generator is operated to provide six different predetermined phase positions, said first and second counters being so constructed that a group comprising like signal steps of one binary state is operative to actuate said forward-backward counter to effect one of said predetermined phase shifts, groups beginning with a step of such one binary state, followed by steps of either binary state are operative to actuate said forward-backward counter to effect respective different predetermined phase shifts, and a group comprising like signal steps of the other binary state is operative to actuate said forward-backward counter to effect still a different phase shift, said signal steps of said other binary state occurring only singly or doubly between two successive groups being inoperative to effect actuation of said forward-backward counter whereby no phase shift, a 0* phase position, is effected thereby.

Claim 14

A circuit arrangement according to claim 11, wherein said carrier frequency generator is operative to provide six different phase positions, said first counter being so constructed that a group comprising signal steps of 001 is operative to actuate said forward-backward counter to effect a phase shift of +60*, a group comprising signal steps of 010 is operative to actuate said forward-backward counter to effect a phase shift of -60*, a group comprising signal steps of 001 is operative to actuate said forward-backward counter to effect a phase shift of +120*, a group comprising signal steps of 000 is operative to actuate said forward-backward counter to effect a phase shift of -120*, a group comprising signal steps of 111 is operative to actuate said forward-backward counter to effect a phase shift of 180*, signal steps of 1 occurring only singly or doubly between two successive groups being inoperative to effect actuation of said forward-backward counter, whereby no phase shift, a 0* phase position is effected thereby.

Claim 15

A circuit arrangement according to claim 12, wherein the first and second counters each comprise bistable flip-flop stages forming respective threes-counters which are switched over, between a rest position and a working position, by such timing pulses which occur at the step centers of binary information to be transmitted, in which one threes-counter always begins to count on occurrence of an 0 step, while the other threes-counter ascertains a tribit with three 1 steps, said forward-backward counter being operatively connected to the respective threes-counters and actuated in the one or the other direction by the switching over of the first of said threes-counters, when the first step of a binary information group to be transmitted is a 0, in dependence upon the respective binary states of the remaining signal steps of such group, and actuated by the switching over of the second of said threes-counters when each signal step of a group to be transmitted is a 1, said control means being operable responsive to each of the six counting positions for connecting a respective one of the six phase positions of said carrier frequency generator to said output.