GB1306164A - - Google Patents

Info

Publication number
GB1306164A
GB1306164A GB2286870A GB2286870A GB1306164A GB 1306164 A GB1306164 A GB 1306164A GB 2286870 A GB2286870 A GB 2286870A GB 2286870 A GB2286870 A GB 2286870A GB 1306164 A GB1306164 A GB 1306164A
Authority
GB
United Kingdom
Prior art keywords
phase
signal
arrangement
colour
flesh
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
Application number
GB2286870A
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed filed Critical
Publication of GB1306164A publication Critical patent/GB1306164A/en
Expired legal-status Critical Current

Links

Classifications

    • HELECTRICITY
    • H04ELECTRIC COMMUNICATION TECHNIQUE
    • H04NPICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N9/00Details of colour television systems
    • H04N9/64Circuits for processing colour signals
    • H04N9/643Hue control means, e.g. flesh tone control

Landscapes

  • Engineering & Computer Science (AREA)
  • Multimedia (AREA)
  • Signal Processing (AREA)
  • Processing Of Color Television Signals (AREA)

Abstract

1306164 Colour television MAGNAVOX CO 12 May 1970 [22 Sept 1969] 22868/70 Heading H4F An arrangement for automatically adjusting the phase angle of the chrominance demodulating signal in a NTSC colour television receiver comprises a null detector 38 which compares the phase distribution of the colour energy in the signal as received from 34 with the phase of the reference signal obtained at 32 from the colour burst and determines a phase correction to be effected at 40 to minimize the energy in the reference phase. This correction is based on the assumption that flesh tones often predominate and that since the I phase (flesh) is at 90 degrees to the reference phase ( - Q), adjustment of the latter to maintain the quadrature arrangement will improve the reproduction of flesh tones. Fig. 3 (not shown) illustrates schematically the generation of a measure of "error" of the reference signal phase by adding the positive peak signal from the Q-axis demodulation output to the inverted negative peak signal, and the use of this in a phase corrector in a feedback loop. In an alternative arrangement (Fig. 4, not shown) the output of the -Q reference generator is passed to a circuit where it is varied between about - Q - 40 and - Q + 40 degrees in sawtooth manner at about 2 c.p.s. and used as demodulating signal in an auxiliary circuit whose output is rectified and smoothed over one frame period. The minimum value of this is detected and used to select the appropriate corrected - Q phase. The arrangement may also be used to adjust the chrominance signal before transmission, using the Q adder to derive the- Q phase reference signal which is then used as above described.
GB2286870A 1969-09-22 1970-05-12 Expired GB1306164A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US85994269A 1969-09-22 1969-09-22

Publications (1)

Publication Number Publication Date
GB1306164A true GB1306164A (en) 1973-02-07

Family

ID=25332129

Family Applications (1)

Application Number Title Priority Date Filing Date
GB2286870A Expired GB1306164A (en) 1969-09-22 1970-05-12

Country Status (3)

Country Link
CA (1) CA997058A (en)
DE (1) DE2029121A1 (en)
GB (1) GB1306164A (en)

Also Published As

Publication number Publication date
CA997058A (en) 1976-09-14
DE2029121A1 (en) 1971-04-15

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Legal Events

Date Code Title Description
PS Patent sealed
PLNP Patent lapsed through nonpayment of renewal fees