US2491918A - Stereophonic receiving system - Google Patents

Stereophonic receiving system Download PDF

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US2491918A
US2491918A US2491918DA US2491918A US 2491918 A US2491918 A US 2491918A US 2491918D A US2491918D A US 2491918DA US 2491918 A US2491918 A US 2491918A
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    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04H—BROADCAST COMMUNICATION
    • H04H20/00—Arrangements for broadcast or for distribution combined with broadcast
    • H04H20/86—Arrangements characterised by the broadcast information itself
    • H04H20/88—Stereophonic broadcast systems

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  • This invention relates to a receiver for sound images which are taken stereophonically and transmitted separately and which are supplied through at least partly separated receiving channels to reproducing devices that are separated in space.
  • At least two transmitting channels are required.
  • the transmission by means of two transmitting channels may, for instance, take place by modulating and transmitting the two sound images on diiierent carrier waves.
  • the two side bands of a single carrier wave may be utilized to constitute transmitting channels. In principle satisfactory stereophcnic transmission is possible in either way.
  • the overall gain of the transmission channels which may be defined as being the ratio between the signal strength on reception and that on transmission, is generally not the same for the two sound images.
  • the invention is based on the recognition that a normal automatic amplification control of the receiving channels is not sufiicient to avoid this distortion.
  • a control oscillation is transmitted with each sound image and the amplification of at least one Of the receiving channels is controlled automatically, in accordance with the intensity diiierences of the control oscillations, in such a manner that the influence of differences in the overall gain for the two sound images on the reproduced resulting sound image is eliminated at least for the greater part.
  • any of them may act as a control oscillation. If, in contradistinction thereto, a single carrier wave is used for the transmission of the two sideban-ds of one carrier wave, at least one additional oscillation must be emitted as a control oscillation. In this case preferably two control oscillations are added which are located on either side of the carrier wave.
  • the receiver is preferably designed in such a manner that each of the receiving channels is controlled in the aforesaid manner. Furthermore it is advisable that the amplification of at leastv one of the receiving channels of the resound images.
  • the amplification of at least one of the receiving channels may also be controlled automatically in accordance with the average intensity of the two incoming control oscillations.
  • the amplification of one or more stages in at least one of the receiving channels is preferably controlled in accordance with the average intensity of the incoming control oscillations, the amplification of one or more of the next stages being controlled in accordance with the intensity differences of the control oscillations.
  • a very simple receiver is obtained by rectifying each of the incoming and amplified control oscillations by means of a single rectifier and by so combining the rectified control oscillations as to obtain at least two control voltages appropriate for automatic control. The value of one of these control voltages depends on the intensity differences of the control oscillations and that of the other control voltage depends on the average intensity of the incoming oscillations.
  • a receiver according to the invention is represented schematically.
  • the receiver is designed for receiving a transmission in which two stereophonically taken sound images are transmitted. This transmission takes place separately.
  • the receiver comprises two receiving channels each of which amplifies and reproduces one of the The two sound images are transmitted on different carrier waves which act at the same time as control oscillations for the auto matic amplification control.
  • the oscillations picked up by an antenna are first of all-amplified by high-frequency amplifiers I0, 20, then-frequency-transformed in mixing stages II, 2
  • the amplification of the amplifiers l0, l2 and 2G, 22 respectively is controlled, as indicated by arrows in the figure.
  • From the rectifiers I4, 24 is taken a control voltage which is a measure of thedifference in receiving intensity of, the two carrier waves.
  • the amplification of the intermediate frequency amplifiers I3, 23 is controlled in such a manner that the amplification of the receiving channelhaving the smaller carrier-wave amplitude is increased and that of the other channel is decreased.
  • a control voltage that is a measure of the intensity difference of the two carrier waves may be supplied to the amplifier 23 and the output voltage of the rectifier 24 to another amplifier, e. g. the amplifier 22. In this way a differential control can be established without first producing a differential control voltage.
  • FIG. 2 A still better result is obtained by means of the receiver schematically represented in Fig. 2.
  • This receiver is difierent from that shown in Fig. 1 in that the rectifiers IT and 21 are missing and furthermore in that there is only one set of intermediate-frequency amplifiers i2, 22.
  • the control voltages are now directly taken from the rectifiers hi, 2d.
  • One control voltage controls automatically the amplification of the high-frequency amplifiers It, 2i] in accordance with the average intensity of the two incoming control oscillations.
  • the other control voltages provide for the differential control of the amplifiers I2, 22 in such a manner that the amplification of the receiving channel having the smaller control oscillation is increased and that of the channel having the larger control oscillation is reduced.
  • the two controls are indicated by arrows.
  • Fig. 3 a diagram of a receiver shown in Fig. 2 is further elaborated.
  • the two high-frequency amplifiers and the two mixing stages are jointly designated H3 20
  • the intermediate-frequency amplifiers i2, 22 are coupled with the rectifiers I4, 24 through intermediate-frequency band-pass filters I8, 28.
  • the output voltages of these rectifiers are set up across series-connected resistances 30, 3
  • a potentiometer consisting of two-series-connected resistances I9, 29 and being connected to corresponding ends of the resistances 39, 419 permits the obtainment of a control voltage which depends on the average intensity of the incoming control oscillations.
  • this control voltage By means of this control voltage the two highfrequency amplifiers I and are controlled; this control is indicated by arrows in the drawing.
  • the control voltages for the difierential control are obtained byconnecting two potentiometers consisting of resistances 32, I2 and 33, 43 respectively each to opposite ends of the resistances 3
  • the control voltag taken from the potentiometer 32, 42 is supplied through a resistance 44 to the control grid of the intermediate frequency amplifier 22, whereas a control voltage taken from the potentiometer 33, 43 is supplied through a resistance 34 to the control grid of the intermediate-frequency amplifier l2.
  • the low-frequency oscillations are supplied I through resistances 35, 45 to the low-frequency amplifiers I5, 25 and reproduced by loudspeakers I6, 26.
  • the circuit shown in Fig. 3 has the advantage 'over that shown in Fig. 1 in that each incoming carrier wave requires only one amplifier; of, the two rectifiers required in total the difierent control voltages and, as the case may be, the lowfrequency oscillations to be reproduced may be taken.
  • first amplification channel means means to apply a first stereophonic sound image component and a first control oscillation having an intensity proportional to the intensity of said first sound image component to said channel means
  • second amplification channel means means to apply a second stereophonic sound image component and a second control oscillation having an intensity proportional to the intensity of said second sound image component to said second channel means
  • first and second spatially separated sound reproducing means coupled to said first and second channel means respectively, and means responsive to the difference in intensity of said control oscillations to vary the amplification of said channels relative to each other in a sense to apply said first and second sound image components to said sound reproducing means in said given intensity ratio.
  • first amplification channel means means to apply a first stereophonic sound image component and a first control oscillation having an intensity proportional to the intensity of said first sound image component to said channel means
  • second amplification channel means means to apply a second stereophonic sound image component and a.
  • second control oscillation having an intensity proportional to the intensity of said second sound image component to said second channel means
  • first and second spatially separated sound reproducing means coupled to said first and second channel means respectively, means to vary the amplification of said first channel means inversely proportional to the intensity of said first control oscillation, and means responsive to the difference in intensity of said control oscillations to vary the amplification of said channels relative to each other in a sense to apply said first and second sound image components to said sound reproducin means in said given intensity ratio.
  • first channel means comprising first and second amplifying stages, means to apply a first stereophonic. sound image component and a first con trol oscillation having an intensity proportional to the intensity of said first sound image component to said channel means, second channel means, means to apply a second stereophonic sound image component and a second control oscillation having an intensity proportional to the intensity of said second sound image component to said second channel means, first and second spatially separated sound reproducing means coupled to said first and second channel means respectively, means coupled to said first 5 channel means to vary the amplification of said first amplifying stage inversely proportional to the intensity or said first control oscillation, and means responsive to the difference in intensity of said control oscillations to vary the amplifica tion of said second amplifying stage in a sense to apply said first and second sound image components to said sound reproducing means in said given intensity ratio.
  • first amplification channel means means to apply a first stereophonic sound image component and a first control oscillation having an intensity proportional to the intensity of said first sound image component to said channel means
  • second amplification channel means means to apply a second sterecphonic sound image component and a sec-- ond control oscillation having an intensity proportional to the intensity of said second sound image component to said second channel means
  • first and second spatially separated sound reproducing means coupled to said first and second channel means respectively, means coupled to said first and second channel means to vary the amplification of said first channel means inversely proportional to the average intensity of said control oscillations, and means responsive to the diiference in intensity of said control oscillations to vary the amplification of said channels relative to each other in a sense to apply said first and second sound image components to said sound reproducing means in said given intensity ratio.
  • first channel means comprising first and second amplifying stages, means to apply a first stereophonic sound image component and a first control oscillation having an intensity proportional to the intensity of said first sound image component to said channel means, second channel means comprising third and fourth amplifying stages, means to apply a second stereophonic sound image component and a second control oscillation having an intensity proportional to the intensity of said second sound image component to said second channel means, first and second spatially separated sound reproducing means coupled to said first and second channel means respectively, means coupled to said first channel means to vary the amplification of said first amplifying stage inversely proportional to the intensity of said first control oscillation, means coupled to said second channel means to vary the amplification of said third amplifying stage inversely proportional to the intensity of said second control oscillation, and means responsive to the diiference in intensity of said control oscillations to vary the amplification of said second and fourth amplifying stages in a
  • first channel means comprising first and second amplifying stages, means to apply a first stereophonic sound image component and a first control oscillation having an intensity proportional to the intensity of said first sound image component to said channel means, second channel means comprising third and fourth amplifying stages, means to apply a second stereophonic sound image component and a second control oscillation having an intensity proportional to the intensity of said second sound image component to said second channel means, first and second spatially separated sound reproducing means coupled to said first and second channel means respectively, means to produce a first control voltage proportional to the average intensity of said first and second control oscillations, means to apply said control voltage to said first and third amplifying stages, means to produce second and third control voltages proportional to the intensity difference between said first and second control oscillations, means to apply said second control voltage to said second amplifying stage, and means to apply said third control voltage to said fourth amplifying stage, said second and third control voltages being applied to said

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  • Engineering & Computer Science (AREA)
  • Signal Processing (AREA)
  • Stereophonic System (AREA)
  • Stereo-Broadcasting Methods (AREA)

Description

Dec. 20, 1949 K. DE BOER ET AL 2,491,9I &
STEREOPHONIC RECEIVING SYSTEM Filed July 2, 1946 V fig. 1.
/I1 12 17 1.7 HIGH INTERMEDIATE INTERMEDIATE LOW FREQUENCY MIXER FREQUENCY FREQUENCY RECTIFIERP FREQUENCY AMPLIFIER AMPLIFIER. AMPLJ FIER, AMPLIFIER LOUD L I WIHER sPEAKER RccTIFIER HIGH INTERMEDIATE I INTERMEDIATE Low FREQLIENcY MIXER FREQUENCY FRE LIENcY IIEcrIFIER- FREquENcY AMPLIFIER AMPLIFIER AMPLIFIER AMPLIFIER I S ESA K ER I 20 31 22 27 23 34 25 26 V 21g. 2.
III 6 H INTERMEDIATE LOW FREQUENCY MIXER FREQUENCY REcrIFIER- FREQUENCY AMPLIFIER AMPLIFIER AMPLIFIER LOUD SPEAKER H IG H INTERMEDIATE LOW FREQUENCY-- MIXER FREQUENCY RECTIFJHZ FREQUENCY AMPLIFIER AMPLIFIER AMPLIFIER SPEA 20 I 36 I In IIIGH FRE uEIIcY I LOW A PLIFIER FREQUENCY AMI) MIXER AMPLIFIER LOUD) SPEAKER J1 J4 5' HIGH FRERIIENcI 45 AMPLIFIER 36 AND MIXER LOW FREQUENCY 20 AMPLIFIER LOUD 1 45 SPEAKER JNVENTORS KORZIZELIS DEBOER ROELOF VERZIIEULEZI AGE/VT I I I I Patented Dec. 20, 1949 STEREOPHONIC RECEIVING SYSTEM Kornelis de Boer and Roelof Vermculen, Eludhoven, Netherlands, assignors to Hartford National Bank and Trust Conn, as trustee Company, Hartford,
Application July 2, 1946, SerialNo. 680,894 In the Netherlands March 19, 1943 Section 1, Public Law 690, August 8, 1946 Patent expires March 19, 1963 6 Claims.
This invention relates to a receiver for sound images which are taken stereophonically and transmitted separately and which are supplied through at least partly separated receiving channels to reproducing devices that are separated in space.
For transmitting stereophonically taken sound images at least two transmitting channels are required. The transmission by means of two transmitting channels may, for instance, take place by modulating and transmitting the two sound images on diiierent carrier waves. When for a stereophonic transmission, two different carrier waves are not available, the two side bands of a single carrier wave may be utilized to constitute transmitting channels. In principle satisfactory stereophcnic transmission is possible in either way.
Due to fading, however, the overall gain of the transmission channels, which may be defined as being the ratio between the signal strength on reception and that on transmission, is generally not the same for the two sound images.
If, however, the overall gain for the two sound images is not equal, distortion of the resulting sound image occurs.
The invention is based on the recognition that a normal automatic amplification control of the receiving channels is not sufiicient to avoid this distortion.
According to the invention, a control oscillation is transmitted with each sound image and the amplification of at least one Of the receiving channels is controlled automatically, in accordance with the intensity diiierences of the control oscillations, in such a manner that the influence of differences in the overall gain for the two sound images on the reproduced resulting sound image is eliminated at least for the greater part.
When the transmission of the sound images takes place through different carrier waves any of them may act as a control oscillation. If, in contradistinction thereto, a single carrier wave is used for the transmission of the two sideban-ds of one carrier wave, at least one additional oscillation must be emitted as a control oscillation. In this case preferably two control oscillations are added which are located on either side of the carrier wave.
The receiver is preferably designed in such a manner that each of the receiving channels is controlled in the aforesaid manner. Furthermore it is advisable that the amplification of at leastv one of the receiving channels of the resound images.
ceiver should also be controlled in accordance with the intensity of the incoming associated control oscillation. Excellent results are obtained by controlling the amplification of one or more stages in at least one of the receiving channels in accordance with the intensity of the incoming associated control oscillation, the amplification of one or more of the next stages being controlled in accordance with the intensity differences of the control oscillation-s.
Instead of control in accordance with the receiving intensity of the associated control oscillation, the amplification of at least one of the receiving channels may also be controlled automatically in accordance with the average intensity of the two incoming control oscillations.
In this case the amplification of one or more stages in at least one of the receiving channels is preferably controlled in accordance with the average intensity of the incoming control oscillations, the amplification of one or more of the next stages being controlled in accordance with the intensity differences of the control oscillations. A very simple receiver is obtained by rectifying each of the incoming and amplified control oscillations by means of a single rectifier and by so combining the rectified control oscillations as to obtain at least two control voltages appropriate for automatic control. The value of one of these control voltages depends on the intensity differences of the control oscillations and that of the other control voltage depends on the average intensity of the incoming oscillations.
In order that the invention may be clearly 1111- derstood and readily carried into effect it will now be described more fully with reference to the accompanying drawing, given by way of example.
In Fig. l a receiver according to the invention is represented schematically. The receiver is designed for receiving a transmission in which two stereophonically taken sound images are transmitted. This transmission takes place separately. The receiver comprises two receiving channels each of which amplifies and reproduces one of the The two sound images are transmitted on different carrier waves which act at the same time as control oscillations for the auto matic amplification control. The oscillations picked up by an antenna are first of all-amplified by high-frequency amplifiers I0, 20, then-frequency-transformed in mixing stages II, 2|; and subsequently amplified again in intermediatefrequency amplifiers I2, 22 and I3, 23. 5
After that the oscillations are detected in rectifiers i4, 24, amplified in low-frequency amplifiers I5, 25 and reproduced by loudspeakers I6, 26.
which is a measure of the intensity of the incoming associated carrier-wave, the amplification of the amplifiers l0, l2 and 2G, 22 respectively is controlled, as indicated by arrows in the figure. From the rectifiers I4, 24 is taken a control voltage which is a measure of thedifference in receiving intensity of, the two carrier waves. By means of this control voltage the amplification of the intermediate frequency amplifiers I3, 23 is controlled in such a manner that the amplification of the receiving channelhaving the smaller carrier-wave amplitude is increased and that of the other channel is decreased. It is not necessary first of all to derive from the rectified signals a control voltage that is a measure of the intensity difference of the two carrier waves. As an alternative theoutput voltage of the rectifier Hi may be supplied to the amplifier 23 and the output voltage of the rectifier 24 to another amplifier, e. g. the amplifier 22. In this way a differential control can be established without first producing a differential control voltage.
In the drawing the differential control is indicated by arrows. In practice it has been found that thiscontrol permits a satisfactory stereophonic reproduction in spite of fading.
A still better result is obtained by means of the receiver schematically represented in Fig. 2. This receiver is difierent from that shown in Fig. 1 in that the rectifiers IT and 21 are missing and furthermore in that there is only one set of intermediate-frequency amplifiers i2, 22.
The control voltages are now directly taken from the rectifiers hi, 2d. One control voltage controls automatically the amplification of the high-frequency amplifiers It, 2i] in accordance with the average intensity of the two incoming control oscillations. The other control voltages provide for the differential control of the amplifiers I2, 22 in such a manner that the amplification of the receiving channel having the smaller control oscillation is increased and that of the channel having the larger control oscillation is reduced. In the drawing the two controls are indicated by arrows.
In Fig. 3 a diagram of a receiver shown in Fig. 2 is further elaborated.
In this event the two high-frequency amplifiers and the two mixing stages are jointly designated H3 20 The intermediate-frequency amplifiers i2, 22 are coupled with the rectifiers I4, 24 through intermediate-frequency band-pass filters I8, 28. The output voltages of these rectifiers are set up across series-connected resistances 30, 3| and 40, 4| respectively, the junction of the two resistances 30, 3| and 43, H being earthed. By combining the voltages set up across these resistances different control voltages can be obtained.
Thus, for instance, a potentiometer consisting of two-series-connected resistances I9, 29 and being connected to corresponding ends of the resistances 39, 419 permits the obtainment of a control voltage which depends on the average intensity of the incoming control oscillations. By means of this control voltage the two highfrequency amplifiers I and are controlled; this control is indicated by arrows in the drawing. The control voltages for the difierential control are obtained byconnecting two potentiometers consisting of resistances 32, I2 and 33, 43 respectively each to opposite ends of the resistances 3|, and 30, 43 respectively. The control voltag taken from the potentiometer 32, 42 is supplied through a resistance 44 to the control grid of the intermediate frequency amplifier 22, whereas a control voltage taken from the potentiometer 33, 43 is supplied through a resistance 34 to the control grid of the intermediate-frequency amplifier l2.
The low-frequency oscillations are supplied I through resistances 35, 45 to the low-frequency amplifiers I5, 25 and reproduced by loudspeakers I6, 26.
The circuit shown in Fig. 3 has the advantage 'over that shown in Fig. 1 in that each incoming carrier wave requires only one amplifier; of, the two rectifiers required in total the difierent control voltages and, as the case may be, the lowfrequency oscillations to be reproduced may be taken.
' What we claim is:
In a stereophonic sound receiving system having stereophonic sound image components in I a given intensity ratio relative to each other, first amplification channel means, means to apply a first stereophonic sound image component and a first control oscillation having an intensity proportional to the intensity of said first sound image component to said channel means, second amplification channel means, means to apply a second stereophonic sound image component and a second control oscillation having an intensity proportional to the intensity of said second sound image component to said second channel means, first and second spatially separated sound reproducing means coupled to said first and second channel means respectively, and means responsive to the difference in intensity of said control oscillations to vary the amplification of said channels relative to each other in a sense to apply said first and second sound image components to said sound reproducing means in said given intensity ratio.
2.'In a stereophonic sound receiving system having stereophonic sound components in a given intensity ratio relative to each other, first amplification channel means, means to apply a first stereophonic sound image component and a first control oscillation having an intensity proportional to the intensity of said first sound image component to said channel means, second amplification channel means, means to apply a second stereophonic sound image component and a. second control oscillation having an intensity proportional to the intensity of said second sound image component to said second channel means, first and second spatially separated sound reproducing means coupled to said first and second channel means respectively, means to vary the amplification of said first channel means inversely proportional to the intensity of said first control oscillation, and means responsive to the difference in intensity of said control oscillations to vary the amplification of said channels relative to each other in a sense to apply said first and second sound image components to said sound reproducin means in said given intensity ratio.
3. In a stereophonic sound receiving system having stereophonic sound image components in agiven intensity ratio relative to each other, first channel means comprising first and second amplifying stages, means to apply a first stereophonic. sound image component and a first con trol oscillation having an intensity proportional to the intensity of said first sound image component to said channel means, second channel means, means to apply a second stereophonic sound image component and a second control oscillation having an intensity proportional to the intensity of said second sound image component to said second channel means, first and second spatially separated sound reproducing means coupled to said first and second channel means respectively, means coupled to said first 5 channel means to vary the amplification of said first amplifying stage inversely proportional to the intensity or said first control oscillation, and means responsive to the difference in intensity of said control oscillations to vary the amplifica tion of said second amplifying stage in a sense to apply said first and second sound image components to said sound reproducing means in said given intensity ratio.
4. In a stereophonic sound receiving system having stereophonic sound image components in a given intensity ratio relative to each other, first amplification channel means, means to apply a first stereophonic sound image component and a first control oscillation having an intensity proportional to the intensity of said first sound image component to said channel means, second amplification channel means, means to apply a second sterecphonic sound image component and a sec-- ond control oscillation having an intensity proportional to the intensity of said second sound image component to said second channel means, first and second spatially separated sound reproducing means coupled to said first and second channel means respectively, means coupled to said first and second channel means to vary the amplification of said first channel means inversely proportional to the average intensity of said control oscillations, and means responsive to the diiference in intensity of said control oscillations to vary the amplification of said channels relative to each other in a sense to apply said first and second sound image components to said sound reproducing means in said given intensity ratio.
5. In a stereophonic sound receiving system having stereophonic sound image components in a given intensity ratio relative to each other, first channel means comprising first and second amplifying stages, means to apply a first stereophonic sound image component and a first control oscillation having an intensity proportional to the intensity of said first sound image component to said channel means, second channel means comprising third and fourth amplifying stages, means to apply a second stereophonic sound image component and a second control oscillation having an intensity proportional to the intensity of said second sound image component to said second channel means, first and second spatially separated sound reproducing means coupled to said first and second channel means respectively, means coupled to said first channel means to vary the amplification of said first amplifying stage inversely proportional to the intensity of said first control oscillation, means coupled to said second channel means to vary the amplification of said third amplifying stage inversely proportional to the intensity of said second control oscillation, and means responsive to the diiference in intensity of said control oscillations to vary the amplification of said second and fourth amplifying stages in a sense to apply said first and second sound image components to said sound reproducing means in said given intensity ratio.
6. In a stereophonic sound receiving system having sound image components in a given intensity ratio relative to each other, first channel means comprising first and second amplifying stages, means to apply a first stereophonic sound image component and a first control oscillation having an intensity proportional to the intensity of said first sound image component to said channel means, second channel means comprising third and fourth amplifying stages, means to apply a second stereophonic sound image component and a second control oscillation having an intensity proportional to the intensity of said second sound image component to said second channel means, first and second spatially separated sound reproducing means coupled to said first and second channel means respectively, means to produce a first control voltage proportional to the average intensity of said first and second control oscillations, means to apply said control voltage to said first and third amplifying stages, means to produce second and third control voltages proportional to the intensity difference between said first and second control oscillations, means to apply said second control voltage to said second amplifying stage, and means to apply said third control voltage to said fourth amplifying stage, said second and third control voltages being applied to said second and fourth amplifying stages in a sense to apply said first and second sound image components to said soitind reproducing means in said given intensity re 10.
KORNELIS ns BOER. ROELOF VERMEULEN.
REFERENCES CITED The following references are of record in the file of this patent:
UNITED STATES PATENTS Number Name Date 1,641,431 Horton Sept. 6, 1927 1,854,247 Brand et a] Apr. 19, 1932 1,914,103 Bjornson June 13, 1933 1,922,059 Ohl Aug. 15, 1933 1,940,097 Ohl Dec. 19, 1933 2,004,107 Goldsmith June 11, 1935 2,004,126 Moore June 11, 1935 2,027,022 Conklin Jan. 7, 1936 2,305,917 Beers Dec. 22, 1942 2,352,696 De Boer et al July 4, 11944
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Cited By (11)

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US2611036A (en) * 1947-11-12 1952-09-16 Gen Electric Selective sideband transmission and reception system
US2783372A (en) * 1955-08-01 1957-02-26 Rca Corp Automatic gain control system
US2885552A (en) * 1956-07-27 1959-05-05 Oscar A Anderson Particle beam tracking circuit
US2922117A (en) * 1957-08-30 1960-01-19 Ian A Hood Control of multiple pulse signals
DE1080631B (en) * 1954-12-31 1960-04-28 Philips Patentverwaltung Receiver for recording stereophonic broadcasts
US3002088A (en) * 1960-02-15 1961-09-26 Bertram A Trevor Agc for single sideband reception
US3005094A (en) * 1958-09-30 1961-10-17 Rca Corp Automatic gain control circuit
US3067287A (en) * 1957-06-19 1962-12-04 Percival William Spencer Stereophonic sound transmission systems
US3109896A (en) * 1958-10-22 1963-11-05 Philco Corp Radio receiver means employing separable complementary units
US3167614A (en) * 1959-03-16 1965-01-26 Rca Corp Multiplicative stereophonic sound signalling system
US3629718A (en) * 1969-03-20 1971-12-21 Blaupunkt Werke Gmbh Multichannel dynamic level control circuit

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US1914103A (en) * 1931-10-02 1933-06-13 Bell Telephone Labor Inc Signaling system
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US1940097A (en) * 1931-09-17 1933-12-19 Bell Telephone Labor Inc Radio receiving system
US2004107A (en) * 1928-02-20 1935-06-11 Rca Corp Radio receiving system
US2004126A (en) * 1928-11-16 1935-06-11 Rca Corp Antenna selector
US2027022A (en) * 1934-01-13 1936-01-07 Rca Corp Fading elimination
US2305917A (en) * 1941-08-30 1942-12-22 Rca Corp Diversity receiving system
US2352696A (en) * 1940-07-24 1944-07-04 Boer Kornelis De Device for the stereophonic registration, transmission, and reproduction of sounds

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US1641431A (en) * 1925-12-15 1927-09-06 Western Electric Co Communication system
US2004107A (en) * 1928-02-20 1935-06-11 Rca Corp Radio receiving system
US1854247A (en) * 1928-10-30 1932-04-19 American Telephone & Telegraph Multiplex phase discrimination transmission system
US2004126A (en) * 1928-11-16 1935-06-11 Rca Corp Antenna selector
US1922059A (en) * 1930-11-01 1933-08-15 Bell Telephone Labor Inc Radio receiving system
US1940097A (en) * 1931-09-17 1933-12-19 Bell Telephone Labor Inc Radio receiving system
US1914103A (en) * 1931-10-02 1933-06-13 Bell Telephone Labor Inc Signaling system
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Cited By (11)

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Publication number Priority date Publication date Assignee Title
US2611036A (en) * 1947-11-12 1952-09-16 Gen Electric Selective sideband transmission and reception system
DE1080631B (en) * 1954-12-31 1960-04-28 Philips Patentverwaltung Receiver for recording stereophonic broadcasts
US2783372A (en) * 1955-08-01 1957-02-26 Rca Corp Automatic gain control system
US2885552A (en) * 1956-07-27 1959-05-05 Oscar A Anderson Particle beam tracking circuit
US3067287A (en) * 1957-06-19 1962-12-04 Percival William Spencer Stereophonic sound transmission systems
US2922117A (en) * 1957-08-30 1960-01-19 Ian A Hood Control of multiple pulse signals
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US3109896A (en) * 1958-10-22 1963-11-05 Philco Corp Radio receiver means employing separable complementary units
US3167614A (en) * 1959-03-16 1965-01-26 Rca Corp Multiplicative stereophonic sound signalling system
US3002088A (en) * 1960-02-15 1961-09-26 Bertram A Trevor Agc for single sideband reception
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