US2458365A

US2458365A - Television receiver

Info

Publication number: US2458365A
Application number: US696129A
Authority: US
Inventors: George W Fyler
Original assignee: Motorola Inc
Current assignee: Motorola Solutions Inc
Priority date: 1946-09-11
Filing date: 1946-09-11
Publication date: 1949-01-04
Anticipated expiration: 1966-01-04

Description

Jan. 4, 1949. G. w. FYLER TELEVISION RECEIVER Filed Sept, 11, 1 946 2 Sheets-Sheet 1 Jan. 4, 1949. e. w. FYLER TELEVISION RECEIVER 2 Sheets-Sheet '2 Filed Sept. 11, 1946 INVENTO ae' e bNN H llllslzlluL lullilal'llillL 1 u r n Ill lllillli lllll lllllliuli NEE: E525 EBEWQ WEEERQSEZNE 533552 Patented Jan. 4, 1949 TELEVISION RECEIVER George W. Fyler, Lombard, Ill., assignor to Motorola, Inc., a corporation of Illinois Application September 11, 1946, Serial No. 696,129

14 Claims. (01. 250-27) This invention relates generally to television receivers and in particular to a power supply system for producing the voltages required for operation of a television receiver including a cathode ray tube.

In prior television receivers it has been necessary to use relatively large amounts of current at high voltage to provide energy for operation of the cathode ray receiver tube and for deflecting the electron beam thereof. Also in most television receivers a relatively large number of amplifying stages are required which also draw current at high voltage. For the above reasons a power supply network has been necessary which is capable of producing very high voltages, and to provide such a supply a relatively large power transformer has generally been provided. Such a power transformer is objectionable because of the high cost thereof and also because of the size and weight added to the receiver.

Heretofore television receivers of conventional design have required power inputs of 300 watts or more. The large amount of power required prevented the placing of a receiver in a small cabinet because of the difficulty of keeping the components reasonably cool. Also hum efiects from the power supply are more pronounced when the power transformer is near the picture tube. This further prevented placing the television receiver in a small cabinet.

Another difiiculty experienced in the design of television receivers is that at the high frequencies presently used for transmitting television signals, the use of long leads for coupling the radio frequency, oscillator, and intermediate frequency stages, and for providing operating potentials therefor, may produce undesirable coupling and instability. This may be overcome by mounting these stages on a chassis and using the chassis as one connector for the power supply. However, this results in a hot chassis which is in general objectionable because of the danger of a person comin in contact with the chassis and being injured by shock.

It is, therefore, an object of this invention to provide an improved television receiver which is small and relatively simple.

A further object of this invention is to provide a small television receiver having simple and eificient means for providing the potentials required for operation of the television receiver tube and for filtering said potentials.

Another object of this invention is to provide an inexpensive television receiver having a power supply system which does not require a power transformer to reduce the cost of the receiver and to eliminate hum in the picture normally produced by the transformer.

Still another object of this invention is to provide a television receiver in which the undesired coupling caused by the leads is eliminated in so far as is possible.

A still further object of this invention is to provide a television receiver mounted in a cabis net so that the chassis will be arranged to be in easy access through an opening in the cabinet.

A feature of this invention is the provision of a television receiver having a three-wire balanced-load power network which does not require a power transformer.

Another feature of this invention is the provision of a television receiver having a threeewire power supply in which the plate loads of the various tubes of the receiver are connected to the power supply in series and parallel to provide better power efficiency.

A further feature of this invention is the provision of a horizontal deflection generator which operates from relatively low voltage direct current and produces a sawtooth output having a relatively large amplitude.

An additional feature of this invention is the provision of a high voltage power supply for the cathode ray tube which is excited from the horizontal deflection generator and which also produces the high voltage required for operation of the vertical deflection generator.

A still further feature of this invention is the provision of a filtering arrangement for the high voltage which utilizes the capacitors of the horizontal deflection generator and, therefore, does not require a high voltage capacitor.

Still another feature of this invention is the provision of a television receiver having a main chassis which may be grounded and a sub-chassis for supporting the high frequency stages of the receiver which is maintained at a reference potential, the sub-chassis bein supported on and insulated from the main chassis.

Yet another feature of this invention is the provision of a television receiver having a cold main chassis and a hot sub-chassis supported thereon with tubes mounted on the sub-chassis and extending through openings in the main chassis and shields for the tubes mounted on the main chassis.

Further objects, features andadvantages will be apparent from a .consideration of the following description taken in connection with the accompanying drawings in which:

vision receiver of the superheterodyne type capable of receiving modulated composite video signals and sound signals and deriving video, syn chronization, and sound signals therefrom. The very high frequency components of the receiver such as the radio frequency, oscillator and intermediate frequency stage are mounted on a subchassis which is insulated from the main chassis and the relatively low frequency components such as the video and audio amplifiers and deflection generators are mounted directly on the main chassis. A simplified power supply network is used in which selenium rectifiers are used for energizing a three-wire system which operates at relatively low voltages. Various components of the television receiver are energized by the two sections of the network, or the entire network as is required, and are arranged to provide a balanced load thereon. A horizontal deflection generator is provided which operates from the three-wire supply and produces a sawtooth voltage of relatively high magnitude for causing the horizontal deflections of the electron beam. 'A portion of the voltage developed by the horizontal deflection generator is utilized for exciting a high voltage power supply which obtains its input power from the three-wire network and produces a high voltage as required for the second anode of the picture tube. A blocking oscillator is provided for producing the vertical deflecting voltages and is arranged to excite a push-pull amplifier which obtains the necessary high voltage from the bleeder resistor of the high voltage power supply. To further reduce the power requirements of the receiver, the heater of the cathode ray tube is connected in series with the total load'on the power supply so that energy is not unnecessarily lost in balancing and dropping resistors.

Referring now more particularly to the drawings, in Fig. 1 there is illustrated a television receiver having a front panel H with a window l2 therein through which the television receiver tube is viewed. A plurality of controls I3 areprovided on the front of the panel, and a loud spreaker M is positioned against the back there of. The panel is preferably made of a woven mesh through which the sound is transmitted or alternatively may be provided with openings through which the sound is emitted. Fig. 2 is a cross-sectional view and Fig. 3 is a bottom view of the receiver showing only a few of the operating components such as the picture tube I5. mountings it therefor, the loud speaker M, a main chassis for the receiver l? and a sub-chassis l3. It is noted that the sub-chassis is supported on the main chassis by insulating blocks It. The high frequency components of the receiver such as the radio frequency amplifier, oscillator, converter and E stages are mounted on the sub-chassis i8 which will be maintained at a reference potential as will be described. The vacuum tubes 26 illustrate the mounting of the vacuum tubes in these stages on the sub-chassis I8 with shields 2! provided therefor supported on the main chassis l! which is insulated. The other stages of the receiver such as the audio stage is mounted directly on the main chassis I? as illustrated by tube 22. The cabinet has a removable bottom 23 which permits easy access to the main chassis.

Referring now to Fig. 4, the circuit diagram of a television receiver of the superheterodyne type is shown. The various components of the receiver are separated by dotted lines and the func tion thereof indicated thereon. Such of these components as are of standard construction will not be described in detail but will be referred to in such a manner that the operation of the television receiver will be apparent. On the circuit diagram the grounds which are marked in the usual way are connections to the main chassis of the television receiver, and the grounds which are marked as arrow points are grounds to the subchassis which is illustrated as It in Figs. 2 and 3. The receiver includes an antenna circuit 24 having terminals 25 to which an antenna may be connected either by a coaxial cable or by a balance feeder line. Any suitable antenna such as a dipole can be used. When using a coaxial line, connection is made to terminals 25d and 25b and when using a balance line, connection is made to terminals 25a and 250. Condensers 26a, 26b and 260 are provided in the input lines to isolate the antenna from the power supply. These con densers cooperate with center tapped inductance 26d and condensers 25c and 26f to form a high pass filter which is effective to suppress interference at the intermediate frequencies to thereby improve the intermediate frequency rejection ratio. The antenna circuit is tuned to the desired frequency by a plurality of inductances 27. The signals are then amplified in the tuned radio fre quency amplifier 28 which includes a pentode tube 29 and a tuned output circuit comprising a lurality of tunable inductances 30. A local oscillator 3! including a triode 32 and a plurality of tuning condensers 33 is provided for producing oscillations for converting the radio frequency signals into intermediate frequency signals in converter 34. The various inductances in the units 2? and 30 and the condensers in the unit 33 are individually tunable so that four television receiving channels may be set up. Switching means for these units are ganged together so that by a single operation, the antenna, radio frequency amplifier, and oscillator are tuned to the desired frequencies. It is obvious that additional inductance and condenser units may be provided so that any number of channels can be made avail-- able. The converter 3!: includes a triode 35 which may be combined in the same envelope as the triode 32 of the oscillator 3|.

' For the purpose of selectively amplifying the intermediate frequencies, a three tube inter mediate frequency amplifier 35 is provided which includes three pent-odes 3'5, 33 and 353 and associated tuning elements. The video and sound intermediate frequency signals are both passed through the intermediate frequency amplifier 38 and are separated after passing through the video amplifier as is explained in my co-pending application Serial No. 676,651 filed June 14, 1946, subject Television receiver circuit. The amplified intermediate frequency signals are applied to 45- and the sound signal at point 46. This arrangementfor simultaneously detecting and amplifying the video and sound signals is also disclosed in my application Serial No. 676,651 referred to above.

The sound signal obtained at point 46 as described above is applied to the audio limiter 59 which includes pentode 5! and operates in the usual manner and is then applied through coupling condenser 52 to the discriminator and first audio amplifier indicated at 53. This discriminator and audio amplifier may be of any suitable construction but I prefer to use the system as described and claimed in Patent No. 2,404,359, issued July 23, 1946, to Marion E. Bond. The discriminator utilizes two diodes 54 and 55 to provide parallel rectifying paths and a triode 56 to which the amplitude modulated signals produced by the discriminator is applied. The diodes 54 and 55 and triode 53 may all be combined in a single tube if desired. The amplitude modulated audio signal is then further amplified in the audio output stage 51 which includes pentode 58 and the amplified signal is applied to loud speaker It.

The composite video signal at point 45 is applied through coupling condenser 60 to the cathode 6| of the cathode ray tube I5. The con trol grid 62 of the tube is connected to the negative side of the power supply as will be explained and the cathode is biased with respect thereto through potentiometer 63 and resistor 64, the tap of potentiometer 63 being variable to control the intensity of the cathode ray beam and thereby the brightness of the image produced. The cathode ray tube I5 includes grids 65, 66' and 61, grid 66 being arranged to control the focus of the tube. Electrostatic deflection is utilized in the tube, the vertical deflection being controlled by

plates

68 and 69 and horizontal deflection by the plates I and 'II. Potentials for causing vertical deflection are applied to the plates by vertical deflection generator I2 and potentials for horizontal deflection are produced by horizontal deflection generator I3.

The video signal is also applied through resistor I and condenser 16 to the grid of triode H which functions as a clipper to derive the synchronization pulses from the composite video signal, the derived pulses being applied through couplin condenser I9 to synchronization signal amplifier 80. The synchronization signals are then applied through coupling condenser 8! to the grid of triode 82 which functions as a blocking oscillator in the horizontal deflection generator I3. Triodes 80 and 82 may be provided in a single envelope to reduce the number of tubes and thereby save space. The amplified synchronization signals are also applied through a filter system comprising resistors 83 and 84 and condensers 85 and 85 to a triode 81 which functions as a blocking oscillator in the vertical deflection generator 72. The triodes I1 and 8'] may likewise be combined in a single envelope.

The television receiver in accordance with the invention is adapted to be energized from the standard 110 volt alternating current household power supply. In order to provide the power required for operation of the television receiver energy must be available for supplying the heaters for the cathodes of the various tubes and also high potential direct current of various voltages must be available for providin the plate and screen voltages necessary for the tubes and for providing the potentials required for focusing and deflecting the beam of the cathode ray tube. The power supply system in accordance with the invention includes terminals I lit and. IIlI adapted to be connected to a source of volts alternating current, a power switch I92 being included for controlling the energization of the system. To obtain the relatively large current required for the heater of the cathode ray tube itself, this heater, indicated at I03, is connected in series with one side of the power supply so that the entire current drawn by the set may be applied thereto. A resistor I04 is connected in shunt with heater I03 so that by controlling the value of the resistance, the current through the heater I03 can be set at a predetermined desired value up to the total set current. Two series groups of tube heater elements are connected across the 110 volt alternating current power supply, the first including heater I05 of pentode I 06, the function of which will be described, and the heater ID! of output tube 58. A resistor I98 is connected in series with these heaters to control the current drawn thereby. The second series group of heaters includes heater I09 of radio frequency amplifier 29, heater III] which is common to triodes 32 and 35 used in the oscillator and converter, heaters III, H2 and H3 of tubes 31, 38 and 39, respectively, in the intermediate frequency amplifier, heater H4 which is common to triodes 80 and 82, heater I I5 for the pentode 43 in the video amplifier, heater N6 of the limiter 5|, heater II! for the triodes H8 and H9 in the vertical deflection generator, heater I 20 for the triodes TI and 87, and heater I2! for the discriminator and first audio frequency amplifier 53. A resistor I 22 is included in this series circuit for limiting the current flow therein and choke coils I23, I24, I25, I26 and i2! are included between the heaters for decoupling the heaters of the various stages. By-pass condensers I28, I 29 and I 30 are also included for by-passing the radio frequencies.

The connection from terminal IDI continues through switch I62, heater HIS and resistor I 3| to a pair of selenium rectifiers I32 and I33. The selenium rectifiers are connected so that the positive portion of the alternating current cycle is rectified by rectifier I32 and appears across condenser I34 which is connected between the rectifier I32 and the terminal Iilli which forms the other side of the alternating current source. The rectifier I33 is connected to pass only negative currents so that a negative potential appears across condenser I35 connected between rectifier I33 and the common terminal. A three-wire power supply system composed of positive and negative terminals and a center terminal is thereby provided which is generally similar to the well known Edison three-wire system.

It is apparent that there will be relatively large 60 cycle ripple in the voltages across each of the condensers I36 and I35. However, the ripple'in the voltages will be out of phase so that the combined potential across the two condensers will have a cycle ripple which will be of much smaller magnitude than the 60 cycle ripple across each condenser. It is obvious that by completely eliminating the center wire the 60 cycle ripple would be thereby eliminated. However, in order to provide a stable system, and for the purposes to be later explained, it is desired to retain the center wire, a relatively large resistor I36 being placed therein to reduce the effect of the 60 cycle ripple. Resistors I37 and I33 are provided in the positive and negative wires and condensers I39 and M8 are provided across the positive and negative branches, respectively, of the power supply to provide stable operating potentials. It is noted that the rectifying arangement described is generally similar to well known voltage doubler systems.

As willbe described, certain of the operating potentials required for the plate loads of the electron discharge valves are obtained between the positive wire and center wire of the threewire system, certain other potentials are obtained between the negative wire and center wire I and when still greater voltages are required the potential between the negative and positive wires is used. As is indicated by the arrows, the negative wire is connected to the sub-chassis I8 on which the very high frequency components such as the radio frequency and intermediate frequency amplifiers are mounted. The negative wire of the power supply is isolated from the main chassis by condenser I4! and the sub-chassis is isolated from the main chassis by spaced condensers E42 and I43. The cathodes of the tubes in the radio frequency amplifier, oscillator and converter are coupled to this sub-chassis to thereby provide the stability required for high frequency circuits. The plates and screens of these tubes are coupled to the center wire so that the operating potentials for the tubes are obtained from the negative side of the three-wire system.

As previously stated, the intermediate frequency amplifier 35 is also mounted on the subchassis and the operating potentials required thereby are obtained between the negative and positive wires of the power supply system. The tubes 31 and 38 of the intermediate frequency amplifier are connected in series between the negative and positive terminals of the power supply, and the tube 38 is connected across the positive section between the center and positive wires. The connection of tubes 31 and 38 in series tends to retain the balance of the power supply system when the variable resistor 41 is adjusted. This resistor is used for controlling the contrast of the television picture and is effective to change the bias and therefore the plate current of the radio frequency amplifier tube 29 and intermediate frequency amplifier tubes 51 and 38. The cathode 31a of tube 31 is coupled through the resistor 4's to the sub-chassis which is at the negative potential. The plate 311) and screen 370 of tube 3'! are connected in series with the cathode 33a of tube 38. The control grid 33b of tube 38 is connected through tuning inductance 43 to the center wire of the power supply system and the plate 38c is connected through resistors 44 and I45 to the positive side of the three-wire system. The plate current of tube 3'! is controlled by the contrast control 41 which biases the cathode 31a. As the plate-cathode circuits of the tubes 31 and 38 are in series, the direct current through the tubes must be the same so that the plate current of tube 38 is also controlled by contrast control 41. Accordingly, the loads on the positive and negative branches of the power supply system provided by the tubes 3'! and 38 are substantially the same. This reduces unbalance in the system caused by adjustment of the contrast control.

The video amplifier, audio amplifier, synchronization signal amplifier and deflection generators are mounted directly on the main chassis. In order to provide the required operating potentials for video amplifier 42, pentode 43 is connected across the total power supply voltage, the cathode of the pentode being connected to the negative Wire of the power supply and the plate being coupled through its load to the positive wire. Likewise the triode 56 which functions as the first audio amplifier stage is connected across the entire power supply voltage. The pentode 5I in the limiter is connected across the negative portion of the power supply as are the clipper triode Ti and the synchronization amplifier tube 80. The audio output tube 58 is connected to the positive section of the power supply. As the audio output tube 58 draws relatively heavy current, the power supply is substantially balanced when the tubes are connected as just stated. That is, the current through the negative wire and the current through the positive wire are substantially equal and the currents through the center wire are substantially equal and in opposite direction to thereby provide a minimum of current flow therein. The seriesparallel arrangement of connecting the plate loads provides the required operating potentials with a very small amount of power.

Referring now more specifically to the horizontal deflection generator I3, at previously stated the generator includes a triode 82 which functions as a blocking oscillator. The tube includes a cathode I50, grid I5I and plate I52. The plate and grid are connected to the windings I53 and I54 of a transformer in a manner to provide regeneration therebetween. The grid is also connected to coupling condenser 8| to receive synchronization pulses therefrom. The negative side of the power supply network is connected through choke coil I55 to the cathode I50 and the plate is connected to the positive wire through choke coil I56 and variable resistor I49. The coils I55 and I56 are mounted on a common core and are so wound and connected that the inductance between points I63 and I64 is a maximum. It is seen that the total power supply voltage can be applied to the horizontal deflection generator, or the voltage can be reduced by resistor I49 to reduce thereby the amplitude of the generator output. The frequency of the oscillator can be controlled by changing the bias on grid I51 as by adjusting resistor I51 which is connected in series with fixed resistor I58. Condenser I59 acts as a by-pass for resistors I51 and I58. A series circuit it provided between the terminals of the power supply through the choke coils I55 and I56 and condensers I60, I6I and IE2. In order that the system be balanced the total capacitance of the condensers I60 and IEI in series is made substantially equal to the capacitance of I62 and the common connection therebetween is connected to the center wire of the power supply.

In operation, the block oscillator circuit including windings I53 and I54 is adjusted to a frequency substantially five times that of the horizontal synchronization pulses. The choke coils I55 and I55 and condensers I60, IBI and IE2 are so chosen that the series circuit through these components will be resonant at a relatively low frequency, a frequency one-tenth that of the horizontal scanning frequency being suitable. As the coil I56 is connected to the positive wire of the power supply and the coil I 55 is connected to the negative wire, the current through this circuit will cause the condensers I50, I6I and I62 to charge so that the point I63 becomes positive and the point I64 becomes negative. It is noted that this will cause a positive potential on the plate I52 which tends to cause the tube to conduct. When the tube 82 conducts a heavy plate current will flow producing current through the condensers I99, I61 and IE2 in an opposite direction to that produced by the power supply which will cause the point I63 to become negative and the point I54 to become positive. As the natural frequency of the series circuit through the condensers is relatively slow the voltage thereacross will build up linearly until interrupted when the tube 82 conducts. This provides the trace portion of the cycle. The bias of the oscillator will be adjusted so that the tube is just about to conduct when a synchronization pulse is received so that the pulse will start the retrace action. As the natural ire-'- quency of the blocking oscillator is very fast the retrace period will be fast as is desired. If'the frequency of the oscillator is five times the frequency of the horizontal pulses as stated, since the retrace is only one-half a cycle the time required for the retrace would be one-tenth of the total time of one horizontal deflection cycle. The reversing potentials on points I63 and I64 are applied through condensers I95 and IE6 to the horizontal deflecting plates 78 and II, re spectively. The voltage appearing on each plate will swing from positive to negative values and vice versa to thereby provide a relatively large balanced sawtooth voltage across the deflecting plates it and II.

In order to provide high voltage as is required for energizing the plate 14 of the cathode ray receiver tube, the sawtooth voltage appearing across the condenser I68 is applied through resistor I59 to the grid Ill) of the pentode I955. The cathode III of the pentode is connected to the negative wire of the power supply system, the screen 1772 to the center wire, and plate I13 is connected to the positive Wire through the primary portion HG of the auto transformer I15. The primary portion I'M is damped by condenser HS and resistor i771. The entire power supply voltage, therefore, is applied to this tube which is biased by resistor I18 so that the pulse applied to the grid I I causes the tube to conduct during only a portion of the cycle. This will provide a high voltage kick, when the tube is out 01f, across the primary portion I14 of the winding which is in the plate circuit of the tube I06. This voltage is increased by the turns ratio of the transformer so that a higher fluctuating voltage is produced across the entire winding I i5. This voltage is applied to diode rectifier H9 which provides the high voltage required for the anode M of the cathode ray tube. An auxiliary winding IE6 is provided on the transformer for heating the filament of the diode I19.

A bleeder resistor which includes fixed resistors I81 and I32 and potentiometer I 83 is connected across the high voltage power supply. The variable contact on the potentiometer I83 can beadjusted to control the potential on the grid 66 of the cathode ray tube to thereby control the focus. For filtering the high frequency ripple from the high voltage from the rectifier H9, low voltage condensers 184 and I85 are provided. A filtering path is provided through condenser I14, condenser I65, condenser I 90 and condenser II to the center wire of the power supply. A parallel filtering path is provided through con? denser H55, condenser I59 and condenser I62. The utilization of these filtering paths which inv clude condensers necessary in the circuit for other reasons eliminates the use of a separate high voltage condenser as is customary for fllter-.

ing the high voltage power supply.

Referring now to the vertical deflection generator 12, as previously stated the triode 8'I functions as a blocking oscillator to produce voltages of the correct frequency for deflecting the beam of the cathode ray tube in a vertical direction. The tube includes a cathode I99 connected to the negative wire of the power supply system, a grid I9! connected through condenser I92 to the winding I93 of a transformer, and a plate I94 connected through winding I 95 of the transformer and resistor I99 to the positive wire of the power supply. Regenerative action is provided through the windings I93 and I95 of the transformer to provide oscillations of the desired frequency. The grid I9I is biased by resistors I97 and I98, resistor E98 being variable to permit control of the natural frequency of the oscillator. Synchronization pulses are applied to the grid I9! through resistors 83 and 84 and condenser 85 as previously explained to hold the oscillations in step with the synchronization pulses. Resistor 83 and condenser 85 are of such value that the horizontal synchronization pulses are by-passed to a large extent. Resistors i9! and I98 and condenser 86 form a diiferentiating circuit which tends to eliminate the undesired low frequency pulses and provide a bias for triggering the tube 8'! When vertical synchronization pulses are received.

In order to provide suflicient voltages for producing the desired vertical deflection of the cathode ray beam, push-pull amplifier tubes IIS and H9 are coupled to the load resistor I99 of the blocking oscillator. A variable tap is provided on resistor I99 so that the magnitude of the deflection can be controlled by controlling the excitation applied to the tube H8. The cathodes of the amplifiers H8 and H9 are connected through resistor 29!] to the negative wire of the power supply and the plates ZDI and 292 are connected through resistors 203 and 29 i, respectively, to the bleeder resistor so that a high voltage is applied to these tubes. The tube II8 obtains excitation from the blocking oscillator through resistor $99 as previously stated, and the tube I I9 obtains excitation from the plate 29I of tube IIB through the capacity voltage divider composed of condensers 295 and 296. This voltage divider reduces the voltage applied to the grid of tube II 9 so that the output voltages of the tubes H8 and [I9 will be substantially equal and opposite. The push-pull voltage from amplifier tubes H8 and H9 are applied through condensers 209 and 299 to the vertical deflection plates 63 and 59, respectively, of the cathode ray tube. It will be apparent that the tubes H8 and I I9 will draw current from the bleeder resistor in a complementary fashion so that the total plate current of the tubes through the bleeder resistor will be substantially constant.

In a specific model constructed in accordance with the invention, with standard volt alternating current power applied to the terminals I99 and IQ! of the power supply, the current through the heater circuit including resistor I08 was .15 ampere, the current through the circuit including resistor I22 was .3 ampere and the current through the rectifiers was approximately .2 ampere. This made a total load current of approximately .65 ampere. The cathode ray tube used was of the type 7GP4, the filament of which requires .6 ampere. Accordingly, the resistor I04 was chosen sothat approximately .95 ampere was shunted thereby to provide .6 ampere for the filament I03 of the cathode ray tube. Voltages of approximately volts were produced between the positive and negative wires and the center 11 wire of the power supply, thus making the total voltage between the negative and positive Wires approximately 260 volts. When using one section'of a 12SN'1 tube as the blocking oscillator in the horizontal deflection generator 13, and applying the entire 260 volts thereto, voltages varying plus and minus approximately 300 volts were obtained across the sides of the horizontal deflection generator circuit thereby providing a sweep voltage having an amplitude of 600 volts for deflection of the cathode ray beam in a horizontal direction. This voltage was ample for operating a seven inch direct viewing cathode ray tube such as type 7GP4. For producing the high voltage a tube type 50L6 was used and when 260 volts were applied thereto, a kick voltage of approximately 1000 volts was obtained with an average plate current on tube I06 of 45 milliamperes. A transformation ratio of 4.5 to 1 was used to there by provide a voltage of 4500 volts across the winding I which, when applied to a diode rectifier such as type 1Z2, produced a potential of approximately 4000 volts for the anode 14 of the 1GP4 receiver tube. A voltage of approximately 450 volts was applied to the push-pull amplifier tubes H8 and H9 of the vertical deflection generator 12 from the bleeder resistor to thereby provide suflicient Voltage for vertical deflection of the cathode ray beam. As stated above, the input to the high voltage power supply is only 45 milliamperes at 260 volts and therefore the output possible at high voltage is also very small. It is well known that the efliciency of vacuum tubes and high step-up transformers is low and energy for the filament of the rectifier also reduces the output power. However, as the vertical deflection generator operates at low frequency (60 cycles) and the reactance of the stray capacity at this frequency is very high, very small currents are required and sufficient current is available from the bleeder resistor for providing the voltage swing required for vertical deflection. Accordingly, the three-wire power supply system which produced a maximum of approximately 260 Volts was satisfactory for providing all potentials required for operation of the '7GP4 tube as well as providing potentials required for amplifying and detecting the video and sound signals.

Referring again to the high voltage power supply system, instead of operating the tube I06 to produce a high voltage kick, the tube may be operated as a class C amplifier. The sawtooth voltage wave from condenser I60 is distorted by series resistor I69 improving the power efliciency of the amplifier. Using values as previously described it is possible to obtain a Voltage of the order of 150 volts across the primary portion I14 of the transformer I15. By using a transformation ratio of 30 to 1, a voltage of approximately 4500 volts is obtained across the winding I15 which when rectified by diode I19 will produce a direct current voltage in the order of 4000 volts as is required for the anode of the picture tube.- The high voltage power supply may be operated in one of the ways described, or in any other well known manner by which high frequency oscillations are produced in the tube I06, then stepped up in the transformer I15 and converted to direct current in the rectifier I19.

It is seen from the above that I have provided a simplified television receiver circuit which in cludes a power supply system capable of providing satisfactory operation of the cathode ray tube and associated amplifying circuits without the use of a power transformer. This materially reduces the cost and also the size and weight of the television receiver. Also the power supply system is efiicient making the current drain of the set a minimum. The horizontal deflection generator is eifective to provide the deflection voltages required from a relatively low voltage power supply source. Likewise high voltage for operation of the anode of the tube, and satisfactory voltages for vertical deflection of the cathode ray beam are obtained from the low voltage power supply source.

The operation of the set is improved by providing the sub-chassis which is connected to the negative wire of the power supply system to thereby permit the efiective grounding of the radio frequency and intermediate frequency stages of the receiver thereon. This is of great value in providing usable currents at the high frequencies involved. The input circuit is arranged so that either a coaxial or a balanced line can be connected safely. Also the arrangement of the main chassis and the receiver cabinet permits easy servicing of the receiver.

Although I have described certain specific embodiments of my invention, it is apparent that various changes and modifications can be made therein which fall within the intended scope of the invention as defined in the appended claims.

I claim:

1. In a television receiver including a cathode ray tube and a plurality of other thermionic vacuum tubes for translating signals to be displayed on said cathode ray tube and for producing voltages for accelerating and deflecting the beam of said cathode ray tube, and in which said tubes include heaters adapted to be electrically energized and plate loads adapted to be connected across sources of direct current potential; a power supply system adapted to be energized by a source of single phase alternating current, comprising means for connecting said heaters to said alternating current source in a seriesparallel arrangement, a pair of rectifiers connected to said alternating current source in a voltage doubler circuit to provide a direct current network, and means for connecting said plate loads to said direct current network in a seriesparallel arrangement so that the load on said power supply system is made a minimum.

2. In an electronic device as defined in claim 1, a system in which the heaters of all said tubes except said cathode ray tube are connected in two parallel branches and said rectifiers are connected across said branches, said heater of said cathode ray tube being connected in series with said parallel branches and said rectifiers so that the total load current of said receiver flows through said heater of said cathode ray tube.

3. Inv a television receiver including a cathode ray tube having an anode and horizontal and vertical deflection electrodes, a horizontal deflection generator for producing sawtooth voltages on said horizontal deflection electrodes comprising condenser means across which reciprocating voltages are produced, a high voltage power supply for applying high voltage to said anode, means for applying a portion of the voltage produced by said horizontal deflection generator to said high voltage power supply for exciting the same, a vertical deflection generator for producing sawtooth voltages on said vertical deflection electrodes, and resistance means connected in series with said vertical deflection generator across said high voltage power supply to provide operating potential for said vertical deflection generator.

4. In a signal translating device including a direct current power supply having terminals maintained at positive and negative potentials and a terminal maintained at an intermediate potential substantially half way between said positive and negative potentials, an amplifier including first and second electron discharge valves each including at least a cathode, a grid and a plate, means for applying a signal to be amplie fied to said grid of said first valve, means for applying the amplified signal from said plate of said first valve to said grid of said second valve, means including a variable resistor for connecting said cathode of said first valve to said negative terminal, means providing a direct current path between said plate of said first valve and said cathode of said second valve, means for connecting said plate of said second valve to said positive terminal, and means for coupling said grid of said second valve to said terminal of intermediate potential, whereby by control of said resistor the plate current of said first and second valves is controlled.

5. In a television receiver including a cathode ray tube and a plurality of other thermionic tubes for amplifying and detecting audio signals and for accelerating and deflecting the beam of said cathode ray tube and in which certain of said tubes draw substantially fixed plate current and certain other of said tubes having varying plate currents depending upon operating conditions, a power supply system adapted to be energized by a source of single phase alternating current and to provide a direct current voltage of the order of twice the voltage of said source, first and second terminals to which said voltage is applied, means for connecting the plate loads of said tubes which draw fixed current across said terminals in a balanced series-parallel arrangement, and a series circuit including variable control means for connecting the plate loads of said tubes which draw varying plate currents to said terminals, said variable control means controlling the current through said series circuit and being ineffective to change the balance of said series-parallel connected tubes, is not affected thereby.

6. In a television receiver including a cathode ray tube having an anode and electrostatic deflection electrodes, and a generator for producing a sawtooth voltage wave connected to said deflection electrodes, a power supply for producing the high voltage required by said anode comprising an electron discharge valve having an input discharge control electrode and output electrodes, an input circuit for applying a sawtooth voltage wave from said deflection generator to said discharge control electrode of said electron discharge valve to cause said valve to conduct intermittently, a source of potential, a transformer having primary and secondary windings, a rectifier, and an output circuit connecting said source of potential and said primary winding of said transformer in series to said output electrodes of said electron discharge valve, said electron discharge valve interrupting said circuit when said valve ceases to conduct to produce a high voltage in said primary winding, the turns ratio of said transformer windings being such that said voltage in said primary winding is stepped up and a greater voltage is produced in said secondary winding, said rectifier being connected to said secondary winding to producea high direct current potential from said voltage in said secondary winding.

7. In a television receiver including a cathode ray tube having an anode and electrostatic defiection electrode, and a generator for producing a sawtooth voltage wave for said deflection electrode, a power supply for producing the high voltage required by said anode comprising an electron discharge valve, electrical means for applying a sawtooth voltage wave from said generator to said electron discharge valve to cause said valve to conduct intermittently, a source of potential, inductance means including first and second portions, a circuit connecting said source of potential and said first portion of said inductance means in series to said electron discharge valve, said electron discharge valve interrupting said circuit when it ceases to conduct to produce a high voltage pulse in said inductance means, and rectifying means connected across said first and second portions of said inductance means for rectifying said high voltage pulse.

8. In a television receiver including a cathode ray tube having an anode and electrostatic deflection electrodes, a deflection generator for producing a sawtooth voltage wave on said deflection electrodes comprising a plurality of serially connected condensers having a center terminal connected to a reference potential and end terminals on which balanced reciprocating voltages are produced, a first pair of condensers individually connecting said end terminals to said deflection electrodes so that said reciprocating voltages are applied to said electrodes, a high voltage supply for producing high direct current potential for said anode of said cathode ray tube, said high voltage supply being excited by a portion of said sawtooth voltage wave, and a second pair of condensers individually connecting said deflection electrodes to said anode, so that a pair of filtering paths are provided between said anode and said reference potential by said second pair of condensers, said first pair of condensers and said serially connected condensers.

9. In a signal receiving device of the superheterodyne type including a three-wire high voltage power supply system with positive, negative and center wires, and in which the receiving device is arranged to provide a substantially balanced load on said power supply system; an intermediate frequency amplifier including first and second electron discharge valves each having a plate, a cathode and a control grid, means coupling said plate of said first valve to said grid of said second valve for high frequency signal voltages so that said high frequency signal voltages are first amplified in said first valve and then further amplified in said second valve, said plate-cathode circuits of said first and second valves being connected in series for direct current voltages between said positive and negative wires, said cathodes of said first valve being coupled to said negative wire and said plate of said second valve being coupled to said positive wire, means for adjusting the bias of said first valve to control the output current thereof and simultaneously control the output current of said second valve due to said series connection.

10. In a television receiver of the superheterodyne type including a three-wire direct current power supply system with positive, negative and center wires, and in which the receiver is arranged to provide a substantially balanced load on said power supply system; an intermediate frequency amplifier including first and second 15 electron discharge valves each having at least a plate, a cathode and a control grid, means for applying high frequency signal voltages to said grid of said first valve, means couplingsaid plate of said first valve to said grid of said second valve for transmission of high frequency signal voltages so that said high frequency signalvoltages are first amplified in said first valve and then further amplified in said second valve, means for deriving said amplified signal voltages from said plate of said second valve, said plate-cathode circuits of said first and second valves being connected in series for directcurrent voltages between said positive and negative wires, said grid of said second valve being coupled to said center wire, and means for adjusting the bias of said first valve for controlling the current in said output circuit thereof, said valves being so connected that the current in the output circuits thereof are substantially equal and the load on said power supply system is substantially balanced.

11. In a television receiver including a cathode ray tube having means for producing an electron beam which impinges on a screen, an accelerating anode, a focusing electrode, horizontal deflection electrodes and vertical deflection electrodes, means energized by a low voltage direct current power source for providing potentials for said anode and said focusing electrode and for providing sawtooth voltage waves for said deflection electrodes for causing said electron beam to scan said screen horizontally at a first frequency and vertically at a lower frequency to form a picture pattern, said operating means comprising in combination, a high voltage direct current power supply energized from said low voltage source and connected to said anode, said high voltage power supply including a high frequency oscillator and a rectifier, a first sawtooth voltage generator operating at said first frequency energized from said low voltage power source and connected to said horizontal deflection electrodes, a second sawtooth voltage generator operating at said lower frequency connected to said vertical deflection electrodes, and a circuit for energizing said second sawtooth generator and said focus electrode from said high voltage power supply, said circuit including resistance means in series connection with said high voltage supply and said second sawtooth generator for supplying energy to the latter, said circuit also including electrical connecting means between said resistance means and said focusing electrode for applying operating potential to said focusing electrode.

12. In a television receiver including an electrostatic cathode ray tube having means for producing an electron beam which impinges on a screen, an accelerating anode, horizontal deflection electrodes and vertical deflection electrodes, and which receiver operates from a low voltage direct current power source, means for supplying potentials to said anode and sawtooth voltage waves to said deflection electrodes for causing said electron beam to scan said screen horizontally at a first frequency and vertically at a lower frequency to form a picture pattern, comprising in combination, a high voltage power supply energized from said low voltage source and connected to said anode, said high voltage power supply including a high frequency vacuum tube oscillator and a rectifier, a first sawtooth voltage generator operating at said first frequency energized from said low voltage power source and connected to said horizontal deflection electrodes, a second sowtooth voltage generator operating at Said lower f quencyconnected to said Vertical deflection electrodes, said second sawtooth generator requiring an operating potential greater than that of said low voltage source to provide the vertical deflection necessary to form said pattern, and a circuit for energizing said second sawtooth generator from said high voltage power supply, said circuit including resistance means in series connection with said high voltage supply and said second generator for supplying the potential required for operating said second sawtooth generator.

13. In a television receiver including a cathode ray tube having means for producing an electron beam, and electrodes for accelerating, focusing and deflecting said beam to form a picture pattern on a screen, which receiver operates from a low voltage direct current power source, means for applying potentials to said electrodes, comprising in combination, a high voltage direct current power supply energized from said low voltage source and connected to said accelerating electrode, said high voltage power supply including a high frequency vacuum tube oscillator for producing high frequency oscillations and a step up transformer and a rectifier for providing direct current potential from said oscillations having a voltage at least 15 times that of said source voltage, said voltage power supply having small current capacity, a sawtooth voltage generator connected to said deflection electrodes and requiring an operating potential greater than that of said low voltage source, said sawtooth voltage generator operating at a frequency of the order of sixty cycles per second so that the capacitive reactance is of such high value that the current available from said high voltage power supply provides the voltage swing necessary for deflecting said beam vertically to form said picture pattern, and a circuit for energizing said sawtooth generator and said focus electrode from said high voltage power supply, said circuit including resistance means in series connection with said high voltage supply and said sawtooth generator for supplying energy to said generator, said circuit also including electrical connecting means between said resistance means and said focusing electrode for applying operating potential to said focusing electrode.

14. In a televisionreceiver operating from a low voltage direct current source, and which includes a cathode ray tube having a screen, means for producing an electron beam which impinges on said screen, an anode for accelerating said beam, a focusing electrode, and vertical deflection electrodes for causing said beam to scan said screen, the combination in said receiver including, a high voltage direct current power supply energized by the low voltage power supply system including a vacuum tube oscillator and a rectifier, said high voltage power supply being connected to the anode of said tube and providing a high voltage therefor so that said beam travels at high velocity, a sawtooth voltage generator operating at a frequency of the order of sixty cycles per second for producing sawtooth voltage waves on said vertical deflection electrodes of sufficient amplitude to deflect said high velocity beam vertically across said screen, and a circuit for energizing said sawtooth generator and said focus electrodes from said high voltage power supply, said circuit including resistance means in series connection with said high voltage power supply and said sawtooth generator for providing a voltage greater than that of said direct current solurce for said sawtooth nera- 17 tor, said circuit also including electrical connecting means between said resistance means and said focusing electrode for applying operating potential to said focusing electrode, said vertical deflection generator including a pair of Vacuum tubes for producing balanced voltage waves and being connected in parallel to said resistance means so that the current through said resistance means is substantially constant.

GEORGE W. FYLER.

REFERENCES CITED The following references are of record in the file of this patent:

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