System for coding and/or decoding color television signal including luminance and chrominance information

Claim 3

A system for decoding a coded television signal supplied through a transmission line from the coding system as claimed in claim 1, said decoding system comprising: means for producing from said coded television signal coded luminance signal components and coded carrier chrominance signal components; means for producing from said coded luminance signal components for sampled picture elements interspatial luminance signal components for unsampled picture elements lying between said sampled picture elements; means for synthesizing said coded luminance signal components and said interspatial luminance signal components to provide output luminance signals; means for producing interspatial carrier-chrominance signal components for said unsampled picture elements by phase-reversing said carrier chrominance signal components for corresponding picture elements in a scanning line other than those where said unsampled picture elements lie; means for synthesizing said coded carrier-chrominance signal components and said interspatial carrier chrominance signal components to provide output carrier chrominance signals; and means for providing the composite television signals from said output luminance and carrier chrominance signals.

Claim 4

A system for coding as recited in claim 1, wherein said color television signal is applied to both said means for producing sampling pulses and said means for sampling and coding, and wherein said means for producing sampling pulses comprises: a sync separator receiving said color television signal and producing a subcarrier f sc and a horizontal snychronizing signal f H ; means connected to receive said subcarrier f sc from said sync separator for producing a signal 2f sc ; means connected to receive said horizontal synchronizing signal f H from said sync separator for producing a signal (n/2)f H ; and means for combining said signal 2f sc and said signal (n/2)f H to produce said sampling pulses.

Claim 5

A system for coding as recited in claim 3, wherein said means for controlling said sampling pulses includes said means for combining said signal 2f sc and said signal (n/2)f H , said means for controlling causing said signal 2f sc and said signal (n/2)f H to be combined to produce sampling pulses f s according to the relationship: f.sub.s = 2f.sub.sc ± (n/2)f.sub.H.

Claim 6

A system for decoding as recited in claim 2, wherein said means for producing coded luminance signal components and coded carrier chrominance signal components comprises: filter means for separating said chrominance signal component from the composite coded television signal, said filter means having the frequency characteristic H (f) expressed by H (f) = [sin (πf/f.sub.s)]2.cos (4 πf/f.sub.s); delay means for delaying the composite coded television signal for a period of time equal to the time delay of said filter means; and subtractor means for subtracting the output of said filter means from the output of said delay means to produce said coded luminance signal components.

Claim 7

A system for decoding as recited in claim 5, wherein said filter means is a digital filter having a filter characteristic given in terms of the Z-conversion as H (Z) = 1/16(1 - Z.sup.-.sup.1).sup.2 (1 + Z.sup.-.sup.2) (1 + Z.sup.-.sup.4), said digital filter comprising: a first shift register stage connected to receive said coded composite television signal; a first subtraction means for subtracting the output of said first shift register from said coded composite television signal; a second shift register stage connected to receive the output of said first subtraction means; second subtraction means for subtracting the output of said second shift register stage from the output of said first subtraction means; third and fourth shift register stages connected in cascade, said third shift register stage being connected to receive the output of said second subtraction means; first addition means for adding the output of said fourth shift register stage to the output of said second subtraction means; fifth, sixth, seventh and eighth shift register stages connected in cascade, said fifth register stage being connected to receive the output of said first addition means; second addition means for adding the output of said eighth shift register stage to the output of said first addition means; and multiplying means for multiplying the output of said second addition means by 1/16th.

Claim 8

A system for decoding as recited in claim 2, wherein said means for producing interspatial luminance signal components for unsampled picture elements comprises: a shift register connected to receive said coded luminance signal components to generate an output delayed by one sampling period; addition means for adding the output of said shift register to said coded luminance signal components; and multiplying means for multiplying the output of said addition means by a factor of 1/2.

Claim 9

A system for decoding as recited in claim 7, wherein said means for synthesizing said coded luminance signal components and said interspatial luminance signal components comprises a switch means connected to receive the output of said shift register and the output of said multipying means for alternately selecting the coded luminance signal from said shift register and the interspatial luminance signal from said multiplying means.

Claim 10

A system for decoding as recited in claim 2, wherein said means for producing interspatial carrier-chrominance signal components for said unsampled picture elements comprises: a line memory connected to receive said coded carrier chrominance signal components to provide a delay of one scanning line period; and multiplying means for multiplying the output of said line memory by a factor of -1.

Claim 11

A system for decoding as recited in claim 9, wherein said means for synthesizing said coded carrier-chrominance signal components and said interspatial carrier chrominance signal components comprises switch means for alternately selecting said coded carrier-chrominance signal components from said means for producing from said coded television signal said coded carrier chrominance signal components and the interspatial carrier chrominance signal components from said multiplying means.

Claim 12

A system for coding as recited in claim 1, further comprising band compression coding means connected to receive the output of said means for sampling and coding for producing a band-compressed signal.

Claim 13

A system for coding as recited in claim 11, wherein said band-compression coding means operates on the principle of differential pulse code modulation and comprises: subtraction means for subtracting an input signal from the output of said means for sampling and coding; quantizer means for receiving the output of said subtraction means and generating a quantized signal according to a predetermined quantizing characteristic; adding means for adding an input signal to the quantized signal from said quantizing means; and a predictive filter having a predictive function P (Z) given as P (Z) = αZ.sup.-.sup.1 + βZ.sup.-.sup.2 - αβZ.sup.-.sup.3 where α and β are predetermined constants, said predictive filter receiving as its input the output of said addition means and the output of said predictive filter being connected as inputs to both said subtraction means and said addition means.

Claim 14

A system for coding as recited in claim 12, wherein said predictive filter comprises: a first shift register for receiving the input to said predictive filter to generate an output delayed by one sampling period; first multiplying means for multiplying the output of said first shift register by said predetermined constant α; subtraction means for subtracting the output of said first multiplying means from the input of said predictive filter; second and third shift registers connected in cascade, the output of said subtraction means being connected to the input of said second shift register; second multiplying means for multiplying the output of said third register by said predetermined constant β; and addition means for adding the outputs of said first and second multiplying means.

Claim 15

A system for decoding a coded television signal supplied through a transmission line from the coding system as claimed in claim 12, said decoding system comprising: band-compression decoding means for decoding the band-compressed transmitted signal to produce said coded television signal; means for producing from said coded television signal coded luminance signal components and coded carrier chrominance signal components; means for producing from said coded luminance signal components for sampled picture elements interspatial luminance signal components for unsampled picture elements lying between said sampled picture elements; means for synthesizing said coded luminance signal components and said interspatial luminance signal components to provide output luminance signals; means for producing interspatial carrier-chrominance signal components for said unsampled picture elements by phase-reversing said carrier chrominance signal components for corresponding picture elements in a scanning line other than those where said unsampled picture elements lie; means for synthesizing said coded carrier chrominance signal components and said interspatial carrier chrominance signal components to provide output carrier chrominance signals; and means for providing the composite television signals from said output luminance and carrier chrominance signals.

Claim 16

A system for decoding as recited in claim 14, wherein said band-compression decoding means comprises: adding means for adding an input signal to said band-compression coded signal; and a predictive filter having the predictive function P (Z) given as P (Z) = αZ.sup.-.sup.1 + βZ.sup.-.sup.2 - αβZ.sup.-.sup.3 where α and β are predetermined constants, the input of said filter being connected to receive the output of said addition means and the output of said filter being connected as an input to said addition means.

Claim 17

A system for decoding as recited in claim 15, wherein said predictive filter comprises: a first shift register for receiving the input to said predictive filter to generate an output delayed by one sampling period; first multiplying means for multiplying the output of said first shift register by said predetermined constant α; subtraction means for subtracting the output of said first multiplying means from the input of said predictive filter; second and third shift registers connected in cascade, the output of said subtraction means being connected to the input of said second shift register; second multiplying means for multiplying the output of said third shift register by said predetermined constant β; and addition means for adding the outputs of said first and second multiplying means.