Delta modulation system with randomly timed multiplexing capability

Claim 5

In a communication system of the type wherein a digitized analog signal requiring a high bit transmission frequency is multiplexed with a digital information signal that requires on the average a much lower bit transmission frequency, the combination of: a. delta modulating means for generating a stream of bits occurring at high frequency to represent an input analog signal; b. means for introducing at random times into said bit stream selected bit patterns which distinctively represent portions of said low-frequency information signal, such introduced bit patterns replacing portions of said bit stream that otherwise would represent coincident parts of said analog signal; c. means for recognizing each of said introduced bit patterns, irrespective of where it occurs in the bit stream, as uniquely pertaining to said information signal; d. means for generating a correction signal according to the difference between the numerical weight of each bit pattern introduced by means b and the numerical weight of the portion of the bit stream which it replaces; and e. means applying said correction signal to said modulating means (a) for modifying the portion of the bit stream succeeding each introduced bit pattern, thereby to compensate for said difference in weights.

Claim 6

In a communication system of the type wherein a digitized analog signal requiring a high bit transmission frequency is multiplexed with a digital information signal that requires on the average a much lower bit transmission frequency, the combination of: a. delta modulating means for generating a stream of bits occurring at high frequency to represent an input analog signal; b. means for introducing at random times into said bit stream selected bit patterns which distinctively represent portions of said low-frequency information signal, such introduced bit patterns replacing portions of said bit stream that otherwise would represent coincident parts of said analog signal; c. means for recognizing each of said introduced bit patterns, irrespective of where it occurs in the bit stream, as uniquely pertaining to said information signal; d. means for generating a correction signal according to the difference between the numerical weight of each bit pattern introduced by means b and the numerical weight of the portion of the bit stream which it replaces; and e. means applying said correction signal to said modulating means (a) for modifying the portion of the bit stream succeeding each introduced bit pattern, thereby to compensate for said difference in weights.

Claim 7

In a communication system of the type wherein a digitized analog signal requiring a high bit transmission frequency is multiplexed with a digital information signal that requires on the average a much lower bit transmission frequency, the combination of: (a) delta modulating means for generating a stream of bits occurring at high frequency to represent an input analog signal; (b) means for introducing at random times into said bit stream selected bit patterns which distinctively represent portions of said low-frequency information signal, such introduced bit patterns replacing portions of said bit stream that otherwise would represent coincident parts of said analog signal; (c) means for recognizing each of said introduced bit patterns, irrespective of where it occurs in the bit stream, as uniquely pertaining to said information signal; (d) means operable at times when no bit pattern is being introduced into said bit stream by means b for detecting a bit pattern identical with any of said selected bit patterns in the part of said stream which is to be transmitted; (e) means for altering such detected bit pattern so that when transmitted, it will not be identical with any of said selected bit patterns; and f. means for modifying the operation of said delta modulating means in accordance with the difference between the respective numerical weights of each detected bit pattern before and after its alteration.

Claim 8

In a communication system of the type wherein a digitized analog signal requiring a high bit transmission frequency is multiplexed with a digital information signal that requires on the average a much lower bit transmission frequency, the combination of: (a) delta modulating means for generating a stream of bits occurring at high frequency to represent an input analog signal; (b) means for introducing at random times into said bit stream selected bit patterns which distinctively represent portions of said low-frequency information signal, such introduced bit patterns replacing portions of said bit stream that otherwise would represent coincident parts of said analog signal; (c) means for recognizing each of said introduced bit patterns, irrespective of where it occurs in the bit stream, as uniquely pertaining to said information signal; (d) means operable at times when no bit pattern is being introduced into said bit stream by means b for detecting a bit pattern identical with any of said selected bit patterns in the part of said stream which is to be transmitted; (e) means for altering such detected bit pattern so that when transmitted, it will not be identical with any of said selected bit patterns; and f. means for modifying the operation of said delta modulating means in accordance with the difference between the respective numerical weights of each detected bit pattern before and after its alteration.

Claim 9

Transmitting apparatus for generating a pulsed output signal to represent a first input signal whose amplitude is subject to high-frequency variations and a second input signal having pulsed amplitude variations that occur at random times and at a maximum frequency much lower than that of said first input signal, said apparatus comprising: a. a delta modulator for generating binary pulses at high frequency to represent the amplitude variations of said first input signal; b. an output line for the signal generated by said transmitting apparatus; c. storage means interposed between said delta modulator and said output line and normally effective to store as a binary sequence of given length the pulses generated by said delta modulator which are being passed to said output line; D. pulse pattern generating means controlled by said second input signal for supplying to said output line a pulse sequence of said given length having a distinctive binary pattern in response to each pulse of a given binary type which occurs in said second input signal; e. gating means effective whenever said output line is receiving pulses from said pulse pattern generator to prevent said line from receiving the pulses which coincidentally have passed through said storage means, thereby enabling the distinctive pulse pattern which represents the second signal pulse to replace a pulse pattern that otherwise would be supplied by said modulator to said output line; f. weight determining means for ascertaining the difference between the respective numerical weights of the pulse sequence supplied to said output line by said pulse pattern generating means and the pulse sequence that otherwise would have been supplied to said line from said modulator by way of said storage means; and g. weight correcting means for modifying the operation of said delta modulator in accordance with the weight differential thus ascertained.

Claim 10

Transmitting apparatus for generating a pulsed output signal to represent a first input signal whose amplitude is subject to high-frequency variations and a second input signal having pulsed amplitude variations that occur at random times and at a maximum frequency much lower than that of said first input signal, said apparatus comprising: a. a delta modulator for generating binary pulses at high frequency to represent the amplitude variations of said first input signal; b. an output line for the signal generated by said transmitting apparatus; c. storage means interposed between said delta modulator and said output line and normally effective to store as a binary sequence of given length the pulses generated by said delta modulator which are being passed to said output line; D. pulse pattern generating means controlled by said second input signal for supplying to said output line a pulse sequence of said given length having a distinctive binary pattern in response to each pulse of a given binary type which occurs in said second input signal; e. gating means effective whenever said output line is receiving pulses from said pulse pattern generator to prevent said line from receiving the pulses which coincidentally have passed through said storage means, thereby enabling the distinctive pulse pattern which represents the second signal pulse to replace a pulse pattern that otherwise would be supplied by said modulator to said output line; f. weight determining means for ascertaining the difference between the respective numerical weights of the pulse sequence supplied to said output line by said pulse pattern generating means and the pulse sequence that otherwise would have been supplied to said line from said modulator by way of said storage means; and g. weight correcting means for modifying the operation of said delta modulator in accordance with the weight differential thus ascertained.

Claim 11

Transmitting apparatus for generating a pulsed output signal to represent a first input signal whose amplitude is subject to high-frequency variations and a second input signal having pulsed amplitude variations that occur at random times and at a maximum frequency much lower than that of said first input signal, said apparatus comprising: a. a delta modulator for generating binary pulses at high frequency to represent the amplitude variations of said first input signal; b. an output line for the signal generated by said transmitting apparatus; c. storage means interposed between said delta modulator and said output line and normally effective to store as a binary sequence of given length the pulses generated by said delta modulator which are being passed to said output line; d. pulse pattern generating means controlled by said second input signal for supplying to said output line a pulse sequence of said given length having a distinctive binary pattern in response to each pulse of a given binary type which occurs in said second input signal; e. gating means effective whenever said output line is receiving pulses from said pulse pattern generator to prevent said line from receiving the pulses which coincidentally have passed through said storage means, thereby enabling the distinctive pulse pattern which represents the second signal pulse to replace a pulse pattern that otherwise would be supplied by said modulator to said output line; f. sensing means for detecting the presence in said storage means of a pulse sequence representation having a pattern identical with that of a pulse sequence that would be generated by said pulse pattern generating means; g. means controlled by said sensing means for altering the pattern of pulses stored in said storage means whenever such identity is found to exist; and h. weight correcting means for modifying the operation of said delta modulator in accordance with the difference between the respective numerical weights of said stored pulse pattern before and after its alteration.

Claim 12

Transmitting apparatus for generating a pulsed output signal to represent a first input signal whose amplitude is subject to high-frequency variations and a second input signal having pulsed amplitude variations that occur at random times and at a maximum frequency much lower than that of said first input signal, said apparatus comprising: a. a delta modulator for generating binary pulses at high frequency to represent the amplitude variations of said first input signal; b. an output line for the signal generated by said transmitting apparatus; c. storage means interposed between said delta modulator and said output line and normally effective to store as a binary sequence of given length the pulses generated by said delta modulator which are being passed to said output line; d. pulse pattern generating means controlled by said second input signal for supplying to said output line a pulse sequence of said given length having a distinctive binary pattern in response to each pulse of a given binary type which occurs in said second input signal; e. gating means effective whenever said output line is receiving pulses from said pulse pattern generator to prevent said line from receiving the pulses which coincidentally have passed through said storage means, thereby enabling the distinctive pulse pattern which represents the second signal pulse to replace a pulse pattern that otherwise would be supplied by said modulator to said output line; f. sensing means for detecting the presence in said storage means of a pulse sequence representation having a pattern identical with that of a pulse sequence that would be generated by said pulse pattern generating means; g. means controlled by said sensing means for altering the pattern of pulses stored in said storage means whenever such identity is found to exist; and h. weight correcting means for modifying the operation of said delta modulator in accordance with the difference between the respective numerical weights of said stored pulse pattern before and after its alteration.

Claim 13

Apparatus for transmitting a bit stream which represents in digital form a first input signal having high-frequency amplitude variations multiplexed with a second input signal having randomly timed amplitude variations representing bits that occur at a maximum frequency much lower than that of the bits representing said first input signal, said apparatus comprising: a. a delta modulator for generating bits at high frequency to represent the amplitude variations of said first input signal; b. an output line for transmitting the signal generated by said apparatus; c. a shift register interposed between said delta modulator and said output line for storing in sequence the bits generated by said delta modulator; d. data word generating means responsive to each bit of a gIven binary type which occurs in said second input signal for supplying to said output line a data word consisting of a bit sequence having a distinctive pattern to represent such an input bit; e. gating means interposed between said output line and the exit stage of said shift register, said gating means normally being effective to pass bits successively from said exit stage to said output line but preventing such passage while said output line is receiving a data word from said generating means d; f. weight determining means for ascertaining the difference between the numerical weight of each data word generated by means d and the numerical weight of the bit sequence of corresponding length stored in said shift register at the time when generation of said data word commences; and g. weight correction means for controlling the operation of said delta modulator in accordance with the weight differential ascertained by means f so that the portion of the transmitted bit stream which follows each data word is consistent with the waveform of said first input signal.

Claim 14

Apparatus for transmitting a bit stream which represents in digital form a first input signal having high-frequency amplitude variations multiplexed with a second input signal having randomly timed amplitude variations representing bits that occur at a maximum frequency much lower than that of the bits representing said first input signal, said apparatus comprising: a. a delta modulator for generating bits at high frequency to represent the amplitude variations of said first input signal; b. an output line for transmitting the signal generated by said apparatus; c. a shift register interposed between said delta modulator and said output line for storing in sequence the bits generated by said delta modulator; d. data word generating means responsive to each bit of a gIven binary type which occurs in said second input signal for supplying to said output line a data word consisting of a bit sequence having a distinctive pattern to represent such an input bit; e. gating means interposed between said output line and the exit stage of said shift register, said gating means normally being effective to pass bits successively from said exit stage to said output line but preventing such passage while said output line is receiving a data word from said generating means d; f. weight determining means for ascertaining the difference between the numerical weight of each data word generated by means d and the numerical weight of the bit sequence of corresponding length stored in said shift register at the time when generation of said data word commences; and g. weight correction means for controlling the operation of said delta modulator in accordance with the weight differential ascertained by means f so that the portion of the transmitted bit stream which follows each data word is consistent with the waveform of said first input signal.

Claim 15

Apparatus for transmitting a bit stream which represents in digital form a first input signal having high-frequency amplitude variations multiplexed with a second input signal having randomly timed amplitude variations representing bits that occur at a maximum frequency much lower than that of the bits representing said first input signal, said apparatus comprising: a. a delta modulator for generating bits at high frequency to represent the amplitude variations of said first input signal; b. an output line for transmitting the signal generated by said apparatus; c. a shift register interposed between said delta modulator and said output line for storing in sequence the bits generated by said delta modulator; d. data word generating means responsive to each bit of a given binary type which occurs in said second input signal for supplying to said output line a data word consisting of a bit sequence having a distinctive pattern to represent such an input bit; e. gating means interposed between said output line and the exit stage of said shift register, said gating means normally being effective to pass bits successively from said exit stage to said output line but preventing such passage while said output line is receiving a data word from said generating means d; f. sensing means for detecting the presence in said shift register of a bit sequence having a pattern identical with that of a data word of the type generated by means d; g. alteration means controlled by said sensing means for inverting at least one of the bit representations stored in said shift register when such identity is detected by said sensing means; and h. weight correcting means for modifying the operation of said delta modulator in accordance with the change in weight of the bit pattern stored in said shift register due to said bit inversion.

Claim 16

Apparatus for transmitting a bit stream which represents in digital form a first input signal having high-frequency amplitude variations multiplexed with a second input signal having randomly timed amplitude variations representing bits that occur at a maximum frequency much lower than that of the bits representing said first input signal, said apparatus comprising: a. a delta modulator for generating bits at high frequency to represent the amplitude variations of said first input signal; b. an output line for transmitting the signal generated by said apparatus; c. a shift register interposed between said delta modulator and said output line for storing in sequence the bits generated by said delta modulator; d. data word generating means responsive to each bit of a given binary type which occurs in said second input signal for supplying to said output line a data word consisting of a bit sequence having a distinctive pattern to represent such an input bit; e. gating means interposed between said output line and the exit stage of said shift register, said gating means normally being effective to pass bits successively from said exit stage to said output line but preventing such passage while said output line is receiving a data word from said generating means d; f. sensing means for detecting the presence in said shift register of a bit sequence having a pattern identical with that of a data word of the type generated by means d; g. alteration means controlled by said sensing means for inverting at least one of the bit representations stored in said shift register when such identity is detected by said sensing means; and h. weight correcting means for modifying the operation of said delta modulator in accordance with the change in weight of the bit pattern stored in said shift register due to said bit inversion.