US2226994A - Amplitude filter - Google Patents

Amplitude filter Download PDF

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Publication number
US2226994A
US2226994A US17960A US1796035A US2226994A US 2226994 A US2226994 A US 2226994A US 17960 A US17960 A US 17960A US 1796035 A US1796035 A US 1796035A US 2226994 A US2226994 A US 2226994A
Authority
US
United States
Prior art keywords
grid
tube
amplitude
condenser
signals
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
US17960A
Other languages
English (en)
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 claimed from US2631A external-priority patent/US2173495A/en
Application filed by LOEWE RADIO Inc filed Critical LOEWE RADIO Inc
Application granted granted Critical
Publication of US2226994A publication Critical patent/US2226994A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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Classifications

    • 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

  • circuit means which cause the separating. value of the mixture to be be varied corresponding with. the variations in the total amplification.
  • Thesemeans may be constructed as automatically acting or also as manually controlled means.
  • the arrangement according to the invention is of particular importance as regards television receivers, which are to be synchronised from the transmitter andmakes use of a three-electrode valve in connection with a grid leak resistance with a parallel connected capacity.
  • Figure 1 shows one form of the present invention and Figure 2 shows comparative signaling strengths of the detected signals.
  • a receiving rectifier l in Fig. L'for example a push-pull detector, the image current passes over a line 2 through the medium of a a condenser 3 to the Braun tube 4.
  • the line 2 is accordingly traversed by image potentials of the order of for example, approximately :10 volts.
  • the amplitude values for strong and weak reception are shown the values for weak reception being shaded or hatched.
  • theextreme white is entered with +10 volts, and the extreme black with 10 volts.
  • the peaks of the synchronizing impulses in Fig. 2 then have an amplitude of 15 volts.
  • the shaded values apply to weak reception. They are given as :3 volts for the imag and p -4 volts for thesynchronlsationsignals.
  • object of the circuit according to the invention consists in performing an amplitude filtering for example at either of the values -12 or -3.5, and in allowing all impulses to pass which are more negative than th stated value and withholding the remainder.
  • the desiredlimits are 5 shown in dash-dotted lines in Fig. 2 and are designated 6 and 6' respectively.
  • the problem is solved according to the invention for example by a single-grid tube 1 in Fig. 1 in the following manner:
  • the cathode of the tube 1 is connected through a resistance 8 of approximately 0.1 megohm with a positive potention of 3.5 volts as compared with the'grid 9 of the same tube.
  • a condenser 3" of approximately 0.005 mf, which blocks the passage of low frequencies, but 'allows the passage of the short and long synchronisation impulses to-an equal degree.
  • the potential of the anode battery I0 is selected to be such that the anode current only commences when the potential cathode and grid exceeds the blocking value of 3.5 volts.
  • condenser 15 is selected to be so small that it short-circuits the high frequencies, but on the other hand it may be charged in a comparatively short time by the grid current (a suitable value is e. g., approximately 100 mmf.). If the leak resistance I6 were missing, the grid, therefore, would apparently be charged to the highest negative peak value occurring, A control effect in the anode circuit would, therefore, cease altogether. By reason now of the leak resistance It the grid is charged not to the peak value of the maximum negative potential, but to a value that is always less negative to a certain extent.
  • a television receiver wherein picture and synchronizingsignals are received as a modulation of a common carrier frequency and wherein the synchronizing signals have a greater amplitude than any picture signals, means for amplify-' ing the modulated carrier frequency, a demodulator tube having input and output electrodes,
  • a television receiver wherein picture and synchronizing signals are received as a modulation of a common carrier frequency and wherein the synchronizing signals have a greater amplitude than any picture signals, means for amplifying the modulated carrier frequency, a demodulator tubeihaving input and output electrodes, means forapplying the modulated carrier to the input electrode of the demodulator tube whereby detected picture and synchronizing signals are present at the output electrode of said tube with the synchronizing signals extending in a negative direction, a separator tube including a cathode, a control electrode and an output electrode, a source of potential, means including a parallel connected condenser and resistance combination for connecting the control electrode of said separator tube to the negative terminal of the source of potential, means including a load circuit for connecting the output electrode of said separator tube to the positive terminal of the source of potential,means including an impedance for normally'maintaining a positive bias on the cathode relative-to the control.
  • means including a condenser for connecting the cathode of said separator tube to the output elect-rodeof 'said demodulator to vary thepotenti-al of said cathode in accordance with variations in; amplitude and voltage of the detected pictureand synchronizingsignals from a predetermined normalamplitude and voltage value, said resistance and condenser combination being adapted to alter the bias voltage applied to the control electrode of the separator tube in a negative direction in accordance with increases in the sign-al strength of the detected synchronizing sign-alswhereby said separator tube is rendered conductive only upon the presence of synchronizing signals irrespective of the variations pling the control electrode of the sepai'ator tube in the amplitude and voltage of the detected sigto the means for amplifying the modulated carnals, the time constant of said condenser and rier frequency to vary the amplification level resistor combination corresponding to the time thereof.

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  • Engineering & Computer Science (AREA)
  • Multimedia (AREA)
  • Signal Processing (AREA)
  • Picture Signal Circuits (AREA)
  • Television Systems (AREA)
  • Noise Elimination (AREA)
US17960A 1934-01-25 1935-04-24 Amplitude filter Expired - Lifetime US2226994A (en)

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

Publications (1)

Publication Number Publication Date
US2226994A true US2226994A (en) 1940-12-31

Family

ID=32074462

Family Applications (2)

Application Number Title Priority Date Filing Date
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

Family Applications After (1)

Application Number Title Priority Date Filing Date
US46124A Expired - Lifetime US2226999A (en) 1934-01-25 1935-10-22 Television receiver

Country Status (4)

Country Link
US (2) US2226994A (de)
BE (2) BE409174A (de)
FR (2) FR46154E (de)
GB (2) GB452715A (de)

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2432151A (en) * 1943-01-18 1947-12-09 Hammond Laurens Amplifying system
US2498839A (en) * 1947-10-25 1950-02-28 Philco Corp Double time constant automatic volume control circuit
US2585883A (en) * 1946-08-10 1952-02-12 Rca Corp Combination second detector, noise limiter, and gain control circuit
US2605350A (en) * 1948-10-23 1952-07-29 Rca Corp Synchronizing signal separator circuit
US2652450A (en) * 1948-05-29 1953-09-15 Rca Corp Sync separation and automatic gain control
US2688712A (en) * 1950-10-28 1954-09-07 Samuel A Procter Television receiver

Families Citing this family (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE917130C (de) * 1936-08-05 1954-08-26 Telefunken Gmbh Einrichtung zur Daempfung stoerender, einer pericodischen Wechselspannung ueberlagerter Stossspannungen
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 (de) * 1939-05-31 1955-07-07 Hazeltine Corp Fernsehempfangseinrichtung
DE975765C (de) * 1941-12-13 1962-08-23 Philips Nv Vorrichtung zum Empfang von mit Hilfe von Impulsen konstanter Amplitude uebertragenen Signalen
US2572179A (en) * 1949-05-24 1951-10-23 Philco Corp Peak leveling circuit
US2698358A (en) * 1950-11-30 1954-12-28 Rca Corp Video amplifier control by combined a. g. c. and d. c. voltages

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
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
US2688712A (en) * 1950-10-28 1954-09-07 Samuel A Procter Television receiver

Also Published As

Publication number Publication date
BE409174A (de)
GB444049A (en) 1936-03-12
FR786901A (de) 1935-09-12
FR46154E (fr) 1936-03-05
GB452715A (en) 1936-08-24
BE407481A (de)
US2226999A (en) 1940-12-31

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