GB1360522A - Circuit for demodulating a colour difference signal in the pal system colour television signal - Google Patents
Circuit for demodulating a colour difference signal in the pal system colour television signalInfo
- Publication number
- GB1360522A GB1360522A GB1028172A GB1028172A GB1360522A GB 1360522 A GB1360522 A GB 1360522A GB 1028172 A GB1028172 A GB 1028172A GB 1028172 A GB1028172 A GB 1028172A GB 1360522 A GB1360522 A GB 1360522A
- Authority
- GB
- United Kingdom
- Prior art keywords
- switch
- phase
- demodulator
- signal
- chrominance
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
Classifications
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
- H04N9/00—Details of colour television systems
- H04N9/44—Colour synchronisation
- H04N9/455—Generation of colour burst signals; Insertion of colour burst signals in colour picture signals or separation of colour burst signals from colour picture signals
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
- H04N11/00—Colour television systems
- H04N11/06—Transmission systems characterised by the manner in which the individual colour picture signal components are combined
- H04N11/12—Transmission systems characterised by the manner in which the individual colour picture signal components are combined using simultaneous signals only
- H04N11/14—Transmission systems characterised by the manner in which the individual colour picture signal components are combined using simultaneous signals only in which one signal, modulated in phase and amplitude, conveys colour information and a second signal conveys brightness information, e.g. NTSC-system
- H04N11/16—Transmission systems characterised by the manner in which the individual colour picture signal components are combined using simultaneous signals only in which one signal, modulated in phase and amplitude, conveys colour information and a second signal conveys brightness information, e.g. NTSC-system the chrominance signal alternating in phase, e.g. PAL-system
- H04N11/165—Decoding means therefor
Landscapes
- Engineering & Computer Science (AREA)
- Multimedia (AREA)
- Signal Processing (AREA)
- Processing Of Color Television Signals (AREA)
Abstract
1360522 Colour television NIPPON VICTOR KK 6 March 1972 [9 March 1971] 10281/72 Heading H4F A PAL colour television decoder includes two reference subcarrier oscillators each operating at a different constant phase determined by the bursts fed to it, the resulting subcarriers being used, after addition and subtraction, if necessary to demodulate the PAL chrominance signal, a switch being provided to ensure correct demodulation independent of the relative phase of the half-line frequency square wave switching signal controlling the switch and the received PAL signal. In one embodiment, Fig. 4, the subcarrier oscillators 14, 16 are each synchronized by alternate bursts received from switch 11, adder 19 providing a signal of - U axis phase and subtractor 20 providing a signal of + V or - V axis phase which coincides with the modulation axis of the V signal in the line of the PAL signal received when switch 11 is in the position c-a shown. A second switch 37 and a phase inverter 39 are provided to ensure correct operation of demodulator 33. Switch 37 and phase inverter 39 may alternatively be provided between input 30 and demodulator 33 (Fig. 5, not shown); or chrominance and reference signals may be fed directly to demodulator 33, the output from the demodulator being passed through switch 37 and phase inverter 39 (Fig. 6, not shown). Alternatively switch 37 and phase inverter 39 may be provided to receive the input signals from 30 and provide an output to burst gate 32 and demodulator 33 (Fig. 7, not shown). Alternatively burst gate 32 in Fig. 4, may be omitted, each oscillator being provided with a separate burst gate and demodulator 33 receiving its chrominance input from a subtractor receiving the inputs from contacts a and b of switch 11, switch 37 then not being necessary (Fig. 10, not shown); or demodulators 33 and 34 may receive every second line of chrominance directly and repeated via a one-line delay line (Fig. 24, not shown). In a further embodiment, Fig. 13, one subcarrier oscillator 51 provides an output of the average phase of the bursts, i.e. - U phase, and the other subcarrier oscillator 50 provides an output of the average phase of one burst phase and a signal opposite in phase to the other burst phase, i.e. +V or - V phase as in Fig. 2, switch 37 and phase inverter 39 again being provided in the reference or chrominance input to demodulator 33 or in the output of demodulator 33, or they may be dispensed with, separate burst gates being provided for the two oscillators 50, 51, the chrominance input to demodulator 33 being from the equivalent of position 53 in Fig. 13 (Fig. 16, not shown). In a further embodiment (Fig. 20, not shown) an oscillator equivalent to 51 in Fig. 13, is provided, the other oscillator receiving every second burst, the resulting outputs being matrixed to provide the ŒV reference signal, a switch and phase inverter again being provided in one of a number of positions, or demodulator 33 receiving the subtracted outputs of switch contacts 11a and 11b (Fig. 23, not shown).
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP1220171A JPS5148428B1 (en) | 1971-03-09 | 1971-03-09 |
Publications (1)
Publication Number | Publication Date |
---|---|
GB1360522A true GB1360522A (en) | 1974-07-17 |
Family
ID=11798776
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
GB1028172A Expired GB1360522A (en) | 1971-03-09 | 1972-03-06 | Circuit for demodulating a colour difference signal in the pal system colour television signal |
Country Status (7)
Country | Link |
---|---|
JP (1) | JPS5148428B1 (en) |
AU (1) | AU470595B2 (en) |
CH (1) | CH562547A5 (en) |
FR (1) | FR2128745B1 (en) |
GB (1) | GB1360522A (en) |
IT (1) | IT949950B (en) |
NL (1) | NL172814C (en) |
Families Citing this family (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPS5390629U (en) * | 1976-12-24 | 1978-07-25 | ||
FR2383565A1 (en) * | 1977-03-10 | 1978-10-06 | Motorola Inc | Quadrature signal generation for TV colour decoder - is performed by timing circuit at oscillator output and applies signals to demodulators |
-
1971
- 1971-03-09 JP JP1220171A patent/JPS5148428B1/ja active Pending
-
1972
- 1972-03-06 GB GB1028172A patent/GB1360522A/en not_active Expired
- 1972-03-07 IT IT2151772A patent/IT949950B/en active
- 1972-03-08 FR FR7208081A patent/FR2128745B1/fr not_active Expired
- 1972-03-09 CH CH349772A patent/CH562547A5/xx not_active IP Right Cessation
- 1972-03-09 NL NL7203133A patent/NL172814C/en not_active IP Right Cessation
- 1972-03-09 AU AU39836/72A patent/AU470595B2/en not_active Expired
Also Published As
Publication number | Publication date |
---|---|
AU3983672A (en) | 1973-09-13 |
DE2211008B2 (en) | 1976-05-13 |
NL7203133A (en) | 1972-09-12 |
FR2128745A1 (en) | 1972-10-20 |
IT949950B (en) | 1973-06-11 |
CH562547A5 (en) | 1975-05-30 |
AU470595B2 (en) | 1973-09-13 |
DE2211008A1 (en) | 1972-09-14 |
NL172814B (en) | 1983-05-16 |
NL172814C (en) | 1983-10-17 |
JPS5148428B1 (en) | 1976-12-21 |
FR2128745B1 (en) | 1980-02-15 |
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Legal Events
Date | Code | Title | Description |
---|---|---|---|
PS | Patent sealed | ||
435 | Patent endorsed 'licences of right' on the date specified (sect. 35/1949) | ||
PCNP | Patent ceased through non-payment of renewal fee |