Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
254 words
A digital voice switch for use in a speech communication system including a continuously variable delta modulator having comparator means for comparing an input speech signal to be encoded and a synthesized feedback signal and producing a difference signal, quantizing means for receiving said difference signal and a clock signal and generating an output bit stream consisting of binary 1''s and 0''s for transmission by said communication system, a binary 1 being produced when said difference signal is positive and a binary 0 being produced when said difference signal is negative, feedback integrator means connected to receive said output bit stream for producing said synthesized feedback signal having a stepped waveform, and an adaptive feedback control means including a digital level detector connected to receive said output bit stream and producing an output on the detection of a first predetermined number of consecutive 1''s in said output bit stream, low pass filter means connected to receive the output of said digital level detector to produce a control voltage, and a pulse amplitude modulator controlled by said control voltage for modulating the input to said feedback integrator means, said digital voice switch being connected to said digital level detector and comprising: means for detecting a second predetermined number of consecutive binary 1''s in said output bit stream by sampling the output of said digital level detector; and means responsive to said detecting means for gating said output bit stream for transmission by said communications system whenever said second predetermined number of consecutive 1''s is detected.
Claim 2
Dependent Claim
254 words
A digital voice switch for use in a speech communication system including a continuously variable delta modulator having comparator means for comparing an input speech signal to be encoded and a synthesized feedback signal and producing a difference signal, quantizing means for receiving said difference signal and a clock signal and generating an output bit stream consisting of binary 1''s and 0''s for transmission by said communication system, a binary 1 being produced when said difference signal is positive and a binary 0 being produced when said difference signal is negative, feedback integrator means connected to receive said output bit stream for producing said synthesized feedback signal having a stepped waveform, and an adaptive feedback control means including a digital level detector connected to receive said output bit stream and producing an output on the detection of a first predetermined number of consecutive 1''s in said output bit stream, low pass filter means connected to receive the output of said digital level detector to produce a control voltage, and a pulse amplitude modulator controlled by said control voltage for modulating the input to said feedback integrator means, said digital voice switch being connected to said digital level detector and comprising: means for detecting a second predetermined number of consecutive binary 1''s in said output bit stream by sampling the output of said digital level detector; and means responsive to said detecting means for gating said output bit stream for transmission by said communications system whenever said second predetermined number of consecutive 1''s is detected.
Claim 3
Dependent Claim
87 words
The digital voice switch as recited in claim 1 wherein said means for detecting comprises: clock means responsive to said clock signal providing clock pulses at a rate inversely proportional to said predetermined number, shift register means connected to receive the output of said digital level detector and shifting in response to said clock pulses, and an AND gate connected to a selected number of stages of said shift register means and providing an output whenever each of said selected number of stages contains a binary 1.
Claim 4
Dependent Claim
51 words
The digital voice switch as recited in claim 2 wherein said means for detecting further comprises delay means connected to the output of said AND gate for maintaining an output signal to said gating means for a predetermined period of time after said second predetermined number of consecutive 1''s is detected.
Claim 5
Dependent Claim
61 words
The digital voice switch as recited in claim 3 wherein said delay means is a one shot multivibrator providing a gating signal to said gating means and further comprising means responsive to the absence of said gating signal for generating and gating a square wave signal having a frequency of one-half of said clock rate for transmission by said communication system.
Claim 6
Dependent Claim
40 words
The digital voice switch as recited in claim 1 wherein said detecting means includes delay means for maintaining an output signal to said gating meAns for a predetermined period of time after said predetermined number of consecutive 1''s is detected.
Claim 7
Dependent Claim
52 words
The digital voice switch as recited in claim 1 further comprising second means responsive to said detecting means for generating and gating a square wave signal having a frequency of one-half of said clock rate for transmission by said communication system in the absence of said output signal from said detecting means.