US2241919A - Method of segregating synchronization impulses - Google Patents

Method of segregating synchronization impulses Download PDF

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Publication number
US2241919A
US2241919A US256749A US25674939A US2241919A US 2241919 A US2241919 A US 2241919A US 256749 A US256749 A US 256749A US 25674939 A US25674939 A US 25674939A US 2241919 A US2241919 A US 2241919A
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United States
Prior art keywords
impulses
frequency
synchronization
segregating
transformer
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Expired - Lifetime
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US256749A
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English (en)
Inventor
Neidhardt Peter
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Alcatel Lucent Deutschland AG
C Lorenz AG
Original Assignee
Standard Elektrik Lorenz AG
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Filing date
Publication date
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Publication of US2241919A publication Critical patent/US2241919A/en
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    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N5/00—Details of television systems
    • H04N5/04—Synchronising
    • H04N5/08—Separation of synchronising signals from picture signals
    • H04N5/10—Separation of line synchronising signal from frame synchronising signal or vice versa

Definitions

  • This invention relates to methods of and means for segregating synchronization impulses, particularly in a television system for controlling the time base devices thereof.
  • the synchronization impulses thus incoming to a receiving equipment may be segregated in filter devices which select the synchronizing impulse frequency components of the frequency mixture received. It is a well known expedient to employ impulses of shorter duration for synchronizing the line scanning, while longer impulses of lower frequency serve to control the framing oscillations. These impulses of different duration are segregated by means of a filtering device which merely permits the alternating frequency to pass which corresponds to the number of the framing impulses and to the number of line impulses, respectively.
  • the use of such filtering devices for segregating the line and frame scanning synchronizing impulses introduces the disadvantage that the wave front of the image change synchronization impulses does not present the desired steepness.
  • Fig. 1 diagrammatically shows synchronization impulses of diiferent kind, as employed in television systems
  • Fig. 2 schematically shows an arrangement according to my invention.
  • Fig. 1 diagrammatically shows the different synchronization impulses used in television transmitting systems.
  • the short impulses which effect the line synchronization are shown at A, while a framing frequency impulse of longer duration is shown at B.
  • the flattened wave fronts of this impulse depend upon the fact that the current characteristic of rectangular shape contains a plurality of sinusoidal currents according to the law of Fourier.
  • the currents of higher frequency in this frequency mixture which currents define the frequency steepness do not pass the filter tuned to the line frequency since these frequencies correspond to the frequency components of the line synchronizing impulses of short duration.
  • This flattening of the rectangular wave front considerably affects the exact control of the framing frequency time base circuit.
  • the Fig. 2 of the accompanying drawing shows one embodiment of such a transformer device.
  • the image change synchronizing pulses derived from the filtering device 1 are applied across the winding I of the transformer 2.
  • the secondary winding of this transformer is divided into two parts II and III.
  • the winding II is arranged on the portion of the transformer iron core which is to be saturated.
  • An impulse of the configuration shown at B in Fig. 1 which impulse is applied across the winding I of the said transformer becomes induced in the windings III in substantially it original shape, while pulses shown in the lower part of the Fig. 1 are induced in the winding II of the transformer.
  • the sum of these impulses thus induced in the two secondaries of the transformer involves an impulse of the shape as indicated in the upper part a of Fig. 1 by the dashed line, and this pulse which now has the desired wave front steepness is employed for controlling the framing frequency time base circuit 3.
  • a transformer device for improving the wave front steepness of television framing frequency synchronization impulses comprising a core having an unsaturable portion and a saturable portion, a primary winding for receiving said synchronizing impulses, a first secondary on said unsaturable portion of said core, and a second secondary winding on the saturable portion of said core and connected in series with said first secondary winding said serially connected secondary windings servin as the output of said device.
  • a television receiving equipment means receiving image synchronizing impulses of different frequencies, means responsive to the higher of said diITer-ent frequencies for synchronizing the line scanning, means responsive to the lower of said different frequencies for synchronizing the framing frequency oscillations, means to segregate and to apply said synchronization impulses of difierent frequencies to the respective responsive means, and a transformer device to improve the wave front steepness of the framing frequency synchronization impulses, said transformer comprising a primary winding connected across said segregating means, an iron core for said transformer having an unsaturable portion and a saturable portion, a first secondary winding on said unsaturable portion of said iron core and a second secondary winding on the saturable portion of said iron core and connected in series with said first secondary winding, the serially related secondary windings being connected with said lower frequency responsive means.

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  • Engineering & Computer Science (AREA)
  • Multimedia (AREA)
  • Signal Processing (AREA)
  • Regulation Of General Use Transformers (AREA)
US256749A 1938-02-16 1939-02-16 Method of segregating synchronization impulses Expired - Lifetime US2241919A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
DE208861X 1938-02-16

Publications (1)

Publication Number Publication Date
US2241919A true US2241919A (en) 1941-05-13

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ID=5794472

Family Applications (1)

Application Number Title Priority Date Filing Date
US256749A Expired - Lifetime US2241919A (en) 1938-02-16 1939-02-16 Method of segregating synchronization impulses

Country Status (4)

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US (1) US2241919A (en(2012))
BE (1) BE432777A (en(2012))
CH (1) CH208861A (en(2012))
FR (1) FR850339A (en(2012))

Also Published As

Publication number Publication date
CH208861A (de) 1940-02-29
FR850339A (fr) 1939-12-14
BE432777A (en(2012))

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