US2226999A - Television receiver - Google Patents

Television receiver Download PDF

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Publication number
US2226999A
US2226999A US46124A US4612435A US2226999A US 2226999 A US2226999 A US 2226999A US 46124 A US46124 A US 46124A US 4612435 A US4612435 A US 4612435A US 2226999 A US2226999 A US 2226999A
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US
United States
Prior art keywords
signals
impulses
synchronizing
line
transformers
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 - Lifetime
Application number
US46124A
Inventor
Schlesinger Kurt
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.)
LOEWE RADIO Inc
Original Assignee
LOEWE RADIO Inc
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
Priority to BE409174D priority Critical patent/BE409174A/xx
Priority to FR786901D priority patent/FR786901A/fr
Priority to BE407481D priority patent/BE407481A/xx
Priority claimed from US2631A external-priority patent/US2173495A/en
Priority to FR786900D priority patent/FR786900A/en
Priority to FR786335D priority patent/FR786335A/en
Priority to GB2349/35A priority patent/GB452715A/en
Priority to US17960A priority patent/US2226994A/en
Priority to FR46154D priority patent/FR46154E/en
Priority to GB12616/35A priority patent/GB444049A/en
Application filed by LOEWE RADIO Inc filed Critical LOEWE RADIO Inc
Priority to US46125A priority patent/US2147554A/en
Priority to US46124A priority patent/US2226999A/en
Priority to US288974A priority patent/US2248561A/en
Publication of US2226999A publication Critical patent/US2226999A/en
Application granted granted Critical
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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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
    • 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

  • the synchronisation impulses are produced at the transmission end as black impulses, i. e., impulses which may interrupt the aerial current for ya brief space of time, of which impulses, in the manner known per se, a group of the duration of approximately 5% of the length of an image line or less serve for synchronising the commencement of the line, whilst a group of impulses,vthe duration of which corresponds to several lines, cause the synchronism in the change 'ofimage
  • the signals are transmitted as black signals, as in this manner there is also accomplished simultaneously a darkening of the return lines otherwise inter ⁇ fering with the image.
  • FIG. 1 is a circuit wherein combined picture and synchronizing signals are received and separated; and Fig. 2 represents in further schematic form a modification of the circuit of Fig. l.
  • the synchronizing impulses make themselves apparent in the form of a negative peak-potential at the lead 29 leading to the image reproducing device.
  • the impulses are, therefore, separated from the image current, the peak potentials of which they exceed, by a filter valve 30.
  • the synchronizing impulses appear, as is well known, next with the image point impulses representative of the light and shade values of the picture. Separation of the signals is performed on account of the different frequency by means of a'filter including a condenser 32 and a resistor 33, the condenser 32 being, for example, of the order of 0.002 mf. and the resistor 33 being of the order of 8,000 ohms, so that only image-change impulses lasting for approximately one milli-second and shorter periods reach the cathode 3
  • the tube which may .be suitably biased, is preferably a gas-filled diode with a hot cathode formers, 34 and 35, which are serially. connected, l
  • Trans,- former 34 is preferably tuned to the chosen high frequency which may be of the order of 100,000 cycles and mayhave a primary Winding of 400 turns and a secondary winding of 200 turns.
  • VThis transformer is preferably connected with suitable screening means and a center feed, as shown.
  • the secondary transformer is so polarized or wound that the line frequency impulses reachthe terminal 48 with positive sign.
  • the same eifect is performed with respect to the lower frequency (line frequency) impulses by the iron transformer ⁇ 35, which may have a winding of the order of 6,000 to 18,000.
  • the secondary of the transformer 35 is connected over a low pass filter comprising resistor 4l and condenser 42, to a terminal point 43.
  • the resistor 4I may be of the order of .2 megohms and a capacity of the order of 0.01 mf.
  • the terminal points 48 and 43 are then connected with the scanning apparatus or relaxation oscillator for the television received.
  • the direct current included in the impulse signal is employed according to the invention for regulating the degree of amplification of the receiver.
  • This effect is obtained in practice by means of a resistance capacity combination comprising the parallelly connected resistor 46, which may be of the order of 0.5 megohms, and the capacity '41, which may be of the ⁇ order of 0.001 mf. in series with the transformers 34 and 35.
  • the time constant of the circuit, including the resistor 46 and capacity 41 should preferably be of the order of the image repetition rate, (for example 1/5 second) so that the fading regulation which is obtained from the voltage appearing at the terminal point 40 operates sufficiently rapidly to hold the amplification level as desired.
  • the resistor 46 should also be selected soV as to be large as compared to the internal resistor of the tube and the resistor In the modified form of arrangement shown by' Fig. 2, the transformers 34 and 35 maybe replaced where desired, by two parallel auto-trans7 formers 38 and 39. These transformers may be tuned by means of condensers 5I, 52 to the basic frequencies of the line and frame 'synchronizing impulses and connected toground at the mid points.
  • a television receiver of the superheterodyne ⁇ type including an amplier for receiving picture signals and both line and frame synchronizingl signals, wherein the synchronizing signals are each of a polarity representing black in the picture and -of a different duration for line and frame, an'd said" synchronizing signals are of greater amplitude in the black direction than any picture signals, lter means connected in the output circuit of the amplier for separating the synchronizing signals from the picture signals, a pair of transformers connected in the output of the filter means for separating the line and frame synchronizing signals'one from the other,v one of said transformers being tuned to the line frequency synchronizing signals and the other tuned This connection also provides the desired reversal of phase of the synchronizing impulses.
  • oscillation generating means connected to receive the separated synchronizing output energy from the transformers, and a high frequency choke coil connected serially intermediate each transformer output and the oscillation generator means for preventing Aheterodyne frequency energy from reaching the oscillation generating means, said transformers and choke coils being within a common shield.
  • a television receiver of the superheterodyne type including an amplifier for receiving picture signals and both line and frame synchronizing signals, wherein the synchronizing signals are Y eachof a polarity representing black in the picture and of adfferent duration for line and frame, ⁇ and ⁇ y said Ysynchronizing signals are of greater amplitude .in the black direction than any picture signals, lter means connected in the output circuit of the amplifier for separating the synchronizing signals from the picture signals, a pair of transformers serially connected Vin the output of the filter means for separating the line and frame synchronizing 'signals one from the other, one of said transformers being tuned to the line frequency synchronizing signalsv and 'the'

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  • Engineering & Computer Science (AREA)
  • Multimedia (AREA)
  • Signal Processing (AREA)
  • Picture Signal Circuits (AREA)
  • Noise Elimination (AREA)
  • Television Systems (AREA)

Description

TELVIS ION RECEIVER original Filed Jan. 21, 1935 ra Flaw/v4 COA/790A 'H/wey Patented Dec. 31, 1940 UNITEDV STATES 1 `".liELltyrsIoiv RECEIVER Kurt Schlesinger, Berln, Germany, assignor, by
mcsne assignments, `to Loewe Radio, Inc., a corc .poration of NewYork Original application January 21, 1935, Serial No. 2,631. Divided and this application October 22, 1935, Serial No. 46,124. In Germany January z claims. lol. iis-#7.3)
The subject matter of this application is a method of and apparatus for` thepwireless synchronisation of television transmission and is a division of my application Serialy No. 2,631 filed Jan. 21, 1935, since issued as United States Letters Patent No. 2,173,495. In this connection synchronisation impulsesare transmitted simultaneously with the image current frequenciesfin the form of mixed frequencies. These frequen` cies call for separation at the receiver.
The synchronisation impulses are produced at the transmission end as black impulses, i. e., impulses which may interrupt the aerial current for ya brief space of time, of which impulses, in the manner known per se, a group of the duration of approximately 5% of the length of an image line or less serve for synchronising the commencement of the line, whilst a group of impulses,vthe duration of which corresponds to several lines, cause the synchronism in the change 'ofimage In accordance with the invention, the signals are transmitted as black signals, as in this manner there is also accomplished simultaneously a darkening of the return lines otherwise inter` fering with the image.
The drawing shows schematically circuits by which the invention may be practised. In the drawing, Fig. 1 is a circuit wherein combined picture and synchronizing signals are received and separated; and Fig. 2 represents in further schematic form a modification of the circuit of Fig. l.
In the receiving rectifier 22 the synchronizing impulses make themselves apparent in the form of a negative peak-potential at the lead 29 leading to the image reproducing device. The impulses are, therefore, separated from the image current, the peak potentials of which they exceed, by a filter valve 30.
In the lead 29 connected to the output of the receiving amplier the synchronizing impulses appear, as is well known, next with the image point impulses representative of the light and shade values of the picture. Separation of the signals is performed on account of the different frequency by means of a'filter including a condenser 32 and a resistor 33, the condenser 32 being, for example, of the order of 0.002 mf. and the resistor 33 being of the order of 8,000 ohms, so that only image-change impulses lasting for approximately one milli-second and shorter periods reach the cathode 3| of the tube 30, while the lower frequencies are not transmitted. The tube which may .be suitably biased, is preferably a gas-filled diode with a hot cathode formers, 34 and 35, which are serially. connected, l
receive the output from the tube 30. Trans,- former 34 is preferably tuned to the chosen high frequency which may be of the order of 100,000 cycles and mayhave a primary Winding of 400 turns and a secondary winding of 200 turns.
VThis transformer is preferably connected with suitable screening means and a center feed, as shown. The secondary transformer is so polarized or wound that the line frequency impulses reachthe terminal 48 with positive sign. The same eifect is performed with respect to the lower frequency (line frequency) impulses by the iron transformer`35, which may have a winding of the order of 6,000 to 18,000. -The secondary of the transformer 35 is connected over a low pass filter comprising resistor 4l and condenser 42, to a terminal point 43. The resistor 4I may be of the order of .2 megohms and a capacity of the order of 0.01 mf. The terminal points 48 and 43 are then connected with the scanning apparatus or relaxation oscillator for the television received.
It has been found in practice that proper operation of the superheterodyne on the same chassis as that used for the amplitude filter circuit was very diiicult, if not impossible, because from the ultra short wave local oscillator which is provided in the high frequency amplier portion remnant ultra high frequency oscillations pass to the body of the chassis, which may be considered as ground for the receiver. This difculty is overcome and a remedy obtained by the use of positive chokes 44 and 45 for ultra high frequency. The chokes 44 and 45 are preferably mounted or positioned in the leads conducting the synchronising impulses which are passing through the wall of the chassis so that the operation of the lead within the chassis up to the choke is as shown. f
Simultaneously the direct current included in the impulse signal is employed according to the invention for regulating the degree of amplification of the receiver. This effect is obtained in practice by means of a resistance capacity combination comprising the parallelly connected resistor 46, which may be of the order of 0.5 megohms, and the capacity '41, which may be of the `order of 0.001 mf. in series with the transformers 34 and 35. The time constant of the circuit, including the resistor 46 and capacity 41, should preferably be of the order of the image repetition rate, (for example 1/5 second) so that the fading regulation which is obtained from the voltage appearing at the terminal point 40 operates sufficiently rapidly to hold the amplification level as desired. The resistor 46 should also be selected soV as to be large as compared to the internal resistor of the tube and the resistor In the modified form of arrangement shown by' Fig. 2, the transformers 34 and 35 maybe replaced where desired, by two parallel auto- trans7 formers 38 and 39. These transformers may be tuned by means of condensers 5I, 52 to the basic frequencies of the line and frame 'synchronizing impulses and connected toground at the mid points.
appearing in the lead 29, which is originally preferably negative and converted into a positive signa The novel featureswhich I believe to be characteristic of myinvention are set forth with particularity in the appended claims. r
I claim: l
1. A television receiver of the superheterodyne `type including an amplier for receiving picture signals and both line and frame synchronizingl signals, wherein the synchronizing signals are each of a polarity representing black in the picture and -of a different duration for line and frame, an'd said" synchronizing signals are of greater amplitude in the black direction than any picture signals, lter means connected in the output circuit of the amplier for separating the synchronizing signals from the picture signals, a pair of transformers connected in the output of the filter means for separating the line and frame synchronizing signals'one from the other,v one of said transformers being tuned to the line frequency synchronizing signals and the other tuned This connection also provides the desired reversal of phase of the synchronizing impulses.
to the frame synchronizing signals, oscillation generating means connected to receive the separated synchronizing output energy from the transformers, and a high frequency choke coil connected serially intermediate each transformer output and the oscillation generator means for preventing Aheterodyne frequency energy from reaching the oscillation generating means, said transformers and choke coils being within a common shield.
2. A television receiver of the superheterodyne type including an amplifier for receiving picture signals and both line and frame synchronizing signals, wherein the synchronizing signals are Y eachof a polarity representing black in the picture and of adfferent duration for line and frame,`and`y said Ysynchronizing signals are of greater amplitude .in the black direction than any picture signals, lter means connected in the output circuit of the amplifier for separating the synchronizing signals from the picture signals, a pair of transformers serially connected Vin the output of the filter means for separating the line and frame synchronizing 'signals one from the other, one of said transformers being tuned to the line frequency synchronizing signalsv and 'the'
US46124A 1934-01-25 1935-10-22 Television receiver Expired - Lifetime US2226999A (en)

Priority Applications (12)

Application Number Priority Date Filing Date Title
BE409174D BE409174A (en) 1934-01-25
FR786901D FR786901A (en) 1934-01-25
BE407481D BE407481A (en) 1934-01-25
FR786335D FR786335A (en) 1934-01-25 1935-01-24 Television receiver
GB2349/35A GB452715A (en) 1934-01-25 1935-01-24 Television receiver
FR786900D FR786900A (en) 1934-01-25 1935-01-24 TV reception
US17960A US2226994A (en) 1934-01-25 1935-04-24 Amplitude filter
FR46154D FR46154E (en) 1934-01-25 1935-04-26 Television receiver
GB12616/35A GB444049A (en) 1934-01-25 1935-04-27 Amplitude filter particularly for television
US46125A US2147554A (en) 1934-01-25 1935-10-22 Television receiver
US46124A US2226999A (en) 1934-01-25 1935-10-22 Television receiver
US288974A US2248561A (en) 1934-01-25 1939-08-08 Intermediate frequency amplifier for television purposes

Applications Claiming Priority (4)

Application Number Priority Date Filing Date Title
DE452715X 1934-01-25
DE2226994X 1934-04-28
US2631A US2173495A (en) 1934-01-25 1935-01-21 Television receiver
US46124A US2226999A (en) 1934-01-25 1935-10-22 Television receiver

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US2226999A true US2226999A (en) 1940-12-31

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US17960A Expired - Lifetime US2226994A (en) 1934-01-25 1935-04-24 Amplitude filter
US46124A Expired - Lifetime US2226999A (en) 1934-01-25 1935-10-22 Television receiver

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Application Number Title Priority Date Filing Date
US17960A Expired - Lifetime US2226994A (en) 1934-01-25 1935-04-24 Amplitude filter

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US (2) US2226994A (en)
BE (2) BE409174A (en)
FR (2) FR46154E (en)
GB (2) GB452715A (en)

Families Citing this family (13)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE917130C (en) * 1936-08-05 1954-08-26 Telefunken Gmbh Device for damping disruptive, pericodic alternating voltage superimposed surge voltages
GB515427A (en) * 1938-05-31 1939-12-05 Charles Leslie Faudell Improvements in or relating to television and like systems
US2240507A (en) * 1938-10-05 1941-05-06 Hazeltine Corp Television synchronizing and control system
DE929973C (en) * 1939-05-31 1955-07-07 Hazeltine Corp Television receiving device
DE975765C (en) * 1941-12-13 1962-08-23 Philips Nv Device for receiving signals transmitted with the aid of pulses of constant amplitude
US2432151A (en) * 1943-01-18 1947-12-09 Hammond Laurens Amplifying system
US2585883A (en) * 1946-08-10 1952-02-12 Rca Corp Combination second detector, noise limiter, and gain control circuit
US2498839A (en) * 1947-10-25 1950-02-28 Philco Corp Double time constant automatic volume control circuit
US2652450A (en) * 1948-05-29 1953-09-15 Rca Corp Sync separation and automatic gain control
US2605350A (en) * 1948-10-23 1952-07-29 Rca Corp Synchronizing signal separator circuit
US2572179A (en) * 1949-05-24 1951-10-23 Philco Corp Peak leveling circuit
US2688712A (en) * 1950-10-28 1954-09-07 Samuel A Procter Television receiver
US2698358A (en) * 1950-11-30 1954-12-28 Rca Corp Video amplifier control by combined a. g. c. and d. c. voltages

Also Published As

Publication number Publication date
GB444049A (en) 1936-03-12
FR786901A (en) 1935-09-12
BE407481A (en)
GB452715A (en) 1936-08-24
BE409174A (en)
FR46154E (en) 1936-03-05
US2226994A (en) 1940-12-31

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