Pulse code modulation communication system

Claim 2

A pulse code modulation communication system for transmitting information from a plurality of channels comprising means for sequentially and periodically sampling said channels to provide a time division multiplex pulse amplitude modulated signal in which the pulses have an amplitude corresponding to the information at the time of sampling, means for receiving said pulses including compressor means, sample and hold means for periodically sampling said compressed pulses at said receiving means and for holding the same while said next channel is being sampled substantially the same components of said sample and hold means holding adjacent compressed pulses, encoding means connected to said sample and hold means to encode the pulses which are being held to provide a pulse code modulated signal and means responsive to the output of said sample and hold means for centering said compressor means.

Claim 3

A pulse code modulation communication system as in claim 1 wherein said sample and hold means comprises a first amplifier having input and output terminals, a storage capacitor connected between the input and output of said amplifier, and a switch for periodically connecting the amplifier to said receiving means to change the capacitor to a value corresponding to the pulse at the receiving means.

Claim 4

A pulse code modulation communication system for transmitting information from a plurality of channels comprising means for sequentially and periodically sampling said channels to provide a time division multiplex pulse amplitude modulated signal in which the pulses have an amplitude corresponding to the information at the time of sampling, means for receiving said pulses including compressor means, sample and hold means for periodically sampling said compressed pulses at said receiving means and for holding the same while said next channel is being sampled substantially the same components of said sample and hold means holding adjacent compressed pulses, said sample and hold means including a first amplifier having input and output terminals, a storage capacitor connected between the input and output of said first amplifier, and a switch for periodically connecting said first amplifier to said receiving means to change the capacitor to a value corresponding to the pulse at the receiving means, said receiving means including a second amplifier having input and output terminals, said input terminal connected to receive said pulses and said output terminal connected to said switch, feedback means connected between the output of the first amplifier and the input of the second amplifier, and encoding means connected to said sample and hold means to encode the pulses which are being held to provide a pulse Code modulated signal.

Claim 5

A pulse code modulation communication system for transmitting information from a plurality of channels comprising means for sequentially and periodically sampling said channels to provide a time division multiplex pulse amplitude modulated signal in which the pulses have an amplitude corresponding to the information at the time of sampling, means for receiving said pulses including compressor means, sample and hold means for periodically sampling said compressed pulses at said receiving means and for holding the same while said next channel is being sampled substantially the same components of said sample and hold means holding adjacent compressed pulses, said sample and hold means including a first amplifier having input and output terminals, a storage capacitor connected between the input and output of said first amplifier, and a switch for periodically connecting said first amplifier to said receiving means to change the capacitor to a value corresponding to the pulse at the receiving means, said receiving means including a second amplifier having input and output terminals, said input terminal connected to receive said pulses and said output terminal connected to said switch, feedback means connected between the output of the first amplifier and the input of the second amplifier, and encoding means connected to said sample and hold means to encode the pulses which are being held to provide a pulse Code modulated signal.

Claim 6

A pulse code modulation communication system as in claim 1 wherein said sample and hold means includes a first amplifier and where said centering means includes a differential amplifier connected to the output of the first amplifier and serving to compare said output with a reference signal and serving to apply a voltage to said compressor means to center the same.

Claim 7

A pulse code modulation communication system for transmitting information from a plurality of channels comprising means for sequentially and periodically sampling said channels to provide a time division multiplex pulse amplitude modulated signal in which the pulses have an amplitude corresponding to the information at the time of sampling, means for receiving said pulses including compressor means, sample and hold means for periodically sampling said compressed pulses at said receiving means and for holding the same while said next channel is being sampled substantially the same components of said sample and hold means holding adjacent compressed pulses, and encoding means connected to said sample and hold means to encode the pulses which are being held to provide a pulse code modulated signal, said encoding means comprising a plurality of current sources arranged in first and second groups, the first of said groups serving to control the current through a first resistor to thereby give a voltage drop corresponding to the current drawn by the current sources of the first group, and the second group serving to draw current through a second resistor to thereby provide a voltage drop corresponding to the current through said second resistor whereby the range of current for a given number of voltage steps is minimized.

Claim 8

A pulse code modulation communication system for transmitting information from a plurality of channels comprising means for sequentially and periodically sampling said channels to provide a time division multiplex pulse amplitude modulated signal in which the pulses have an amplitude corresponding to the information at the time of sampling, means for receiving said pulses including compressor means, sample and hold means for periodically sampling said compressed pulses at said receiving means and for holding the same while said next channel is being sampled substantially the same components of said sample and hold means holding adjacent compressed pulses, and encoding means connected to said sample and hold means to encode the pulses which are being held to provide a pulse code modulated signal, said encoding means comprising a plurality of current sources arranged in first and second groups, the first of said groups serving to control the current through a first resistor to thereby give a voltage drop corresponding to the current drawn by the current sources of the first group, and the second group serving to draw current through a second resistor to thereby provide a voltage drop corresponding to the current through said second resistor whereby the range of current for a given number of voltage steps is minimized.

Claim 9

A pulse code modulation communication system as in claim 1 together with means for receiving said pulse code modulated signal and to decode the same to provide a time division multiplex pulse amplitude modulated signal, means for receiving said pulse amplitude modulated signal, switching means for sampling said receiving means to sample individual pulses and apply the same to a plurality of output gates, and means including gates for providing output signals corresponding to said input information.

Claim 10

A pulse code modulation communication system as in claim 6 wherein said means including gates includes a blocking gate serving to block said gates whereby said gates can only conduct when said blocking gate is active, and a multivibrator serving to control the active period of said blocking gate.

Claim 11

A pulse code modulation communication system for receiving pulse code modulated information comprising, means for decoding said information to provide a time division multiplex pulse amplitude modulated signal, means for receiving said pulse amplitude modulated signal, sample and hold means for periodically sampling said signal for holding the same for application to a plurality of output gates while succeeding pulse code modulated information is being decoded substantially the same components of said decoding means and sample and hold means decoding and holding adjacent information and signals respectively, and means including gates for providing output signals corresponding to said input information.

Claim 12

A pulse code modulation communication system for receiving pulse code modulated information comprising, means for decoding said information to provide a time division multiplex pulse amplitude modulated signal, means for receiving said pulse amplitude modulated signal, sample and hold means for periodically sampling said signal for holding the same for application to a plurality of output gates while succeeding pulse code modulated information is being decoded substantially the same components of said decoding means and sample and hold means decoding and holding adjacent information and signals respectively, and means including gates for providing output signals corresponding to said input information.

Claim 13

A pulse code modulation communication system as in claim 8 wherein said means including gates includes a blocking gate serving to block said gates whereby said gates can only conduct when said blocking gate is active, and a monostable multivibrator serving to control the active period of said blocking gate.

Claim 14

A pulse code modulation communication system for receiving pulse code modulated information comprising, means for decoding said information to provide a time division multiplex pulse amplitude modulated signal, said decoding means comprising a plurality of current sources arranged in first and second groups, the first of said groups serving to control the current through a first resistor to thereby give a voltage drop corresponding to the current draWn by the current sources of the first group, and the second group serving to draw current through a second resistor to thereby provide a voltage drop corresponding to the current through said second resistor whereby the range of current for a given number of voltage steps is minimized, means for receiving said pulse amplitude modulated signal, sample and hold means for periodically sampling said signal for holding the same for application to a plurality of output gates while succeeding pulse code modulated information is being decoded substantially the same components of said decoding means and sample and hold means decoding and holding adjacent information and signals respectively, and means including gates for providing output signals corresponding to said input information.

Claim 15

A pulse code modulation communication system for receiving pulse code modulated information comprising, means for decoding said information to provide a time division multiplex pulse amplitude modulated signal, said decoding means comprising a plurality of current sources arranged in first and second groups, the first of said groups serving to control the current through a first resistor to thereby give a voltage drop corresponding to the current draWn by the current sources of the first group, and the second group serving to draw current through a second resistor to thereby provide a voltage drop corresponding to the current through said second resistor whereby the range of current for a given number of voltage steps is minimized, means for receiving said pulse amplitude modulated signal, sample and hold means for periodically sampling said signal for holding the same for application to a plurality of output gates while succeeding pulse code modulated information is being decoded substantially the same components of said decoding means and sample and hold means decoding and holding adjacent information and signals respectively, and means including gates for providing output signals corresponding to said input information.