US3697692A - Two-channel,four-component stereophonic system - Google Patents

Two-channel,four-component stereophonic system Download PDF

Info

Publication number
US3697692A
US3697692A US151790A US3697692DA US3697692A US 3697692 A US3697692 A US 3697692A US 151790 A US151790 A US 151790A US 3697692D A US3697692D A US 3697692DA US 3697692 A US3697692 A US 3697692A
Authority
US
United States
Prior art keywords
speakers
amplifiers
impedance
terminals
audio
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
US151790A
Other languages
English (en)
Inventor
David Hafler
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.)
DYNACO Inc
Original Assignee
DYNACO 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
Application filed by DYNACO Inc filed Critical DYNACO Inc
Application granted granted Critical
Publication of US3697692A publication Critical patent/US3697692A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

Links

Images

Classifications

    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04S—STEREOPHONIC SYSTEMS 
    • H04S3/00—Systems employing more than two channels, e.g. quadraphonic
    • H04S3/02—Systems employing more than two channels, e.g. quadraphonic of the matrix type, i.e. in which input signals are combined algebraically, e.g. after having been phase shifted with respect to each other

Definitions

  • speakers in the left and right front comers respond to (L -1- R12 and (R (Is/2), respectively, while in a second embodiment these speakers respectively respond to (L) and (R), respectively.
  • Speakers in the left and right rear corners respond to signals proportional to L (R/2) and R (L/2), respectively.
  • signals received by left and right microphones are assumed to contain front information, i.e., information common to the two microphones, and back information which may be taken to represent hall ambience, or reflections from the back wall directly or via side walls.
  • front information i.e., information common to the two microphones
  • back information which may be taken to represent hall ambience, or reflections from the back wall directly or via side walls.
  • the latter are of random phase, and therefore include cophasal and contraphasal components.
  • Left and right front speakers respond without any change of signals of a two amplifier stereo amplifier system.
  • the system is conventional.
  • Two rear speakers are added to the conventional system. These are located left and right of a listener, and are driven on the left by the left channel signal minus half the right channel signal, and on the right by the right channel signal minus half the left channel signal.
  • the common cophasal components of the two channels subtract in both speakers, by 6db, but the ambience representing components of the signal add, insofar as they are non-cophasal in both speakers.
  • FIG. 1 is a circuit diagram of one embodiment of a reproduction system in accordance with the present invention, wherein negative blending of signals coupled to rear speakers is provided;
  • FIG. 2 is a circuit diagram of a reproduction system in accordance with the present invention wherein positive blending of signals fed to front speakers and negative blending of signals fed to rear speakers is provided;
  • FIG. 3 is a circuit diagram of a modification of embodiment of FIG. 1, employing a fifth speaker;
  • FIG. 4 is a circuit diagram illustrating a fifth speaker located remotely of the four speakers illustrated in FIGS. 1 and 2;
  • FIG. 5 is a circuit diagram of a modification of the system of FIG. 1, employing autotransformers for intercomplying speakers;
  • FIG. 6 is a circuit diagram of embodiment of the in- 60 vention utilizing autotransformers for blending signals supplied only to rear speakers;
  • FIG. 7 is a plan view of a hall arranged for recording signals capable of reproduction according to the systems of FIGS. 1-6, incl.;
  • FIG. 8 is a circuit diagram of microphone circuitry employed in the hall illustrated in FIG. 7.
  • Stereophonic source 11 can be a standard stereophonic signal, of the type derived from conventionally recorded stereophonic sources, such as disc records or magnetic tapes, or from a stereophonic f.m. multiplex receiver.
  • the right and left channels derived from source 11 are applied to input terminals of conventional stereo amplifiers 12 and 13, each of which includes a signal output terminal referenced to ground.
  • the right and left channel output signals of amplifiers l2 and 13 are fed to speakers 21, 22, 23 and 24, positioned approximately in the corners of a quadrilateral listening area 25, which generally is defined by the walls of a room.
  • Speakers 21 and 22 are at the front of the listening area so that a listener in the interior of area 25 is generally positioned so that he is facing them, while speakers 23 and 24 are located in the rear of listening area 25 so that they are facing toward the back of the listener.
  • Speakers 21-24 preferably have matched impedance characteristics, although this is not a necessary requirement, as seen infra, as long as front speakers 21 and 22 and rear speakers 23 and 24 are matched in pairs.
  • speakers 21 and 22 are responsive only to the output signals of amplifiers 12 and 13, respectively.
  • the left and right channel signals are differentially combined at speakers 23, 24, with 6 db of crossover, by feeding the output signals of amplifiers Hand 13 to one input terminal of each of speakers 23 and 24, respectively, and by connecting the other terminal of the speakers to ground through T network 28 and impedance 29.
  • impedance 29 has a value corresponding with the impedance of either of matched rear speakers 23 and 24.
  • impedance 29 can be a resistor if speakers 23 and 24 have a substantially flat impedance versus frequency response over the entire audio spectrum, or the impedance can be a circuit simulating and matching the impedance characteristics of speakers 23 and 24. In the alternative, impedance 29 is a further speaker having impedance characteristics matched with those of speakers 23 and 24.
  • Crossover can differ from 6 db if the relative crossover between the two channels can theoretically vary so that the responses for speakers 23 and 24 are respectively represented as (L KR) and (R KL), where K is a constant between zero and one. In practical situations the value of K will be between 0.25 and 0.75; for 6 db of crossover K 0.5.
  • the negative crossovers from the right channel into the left rear speaker 23 and from the left channel into right speaker 24 provide a differential effect in speakers 23 and 24 relative to the left and right channels to simulate the reflective or reverberative characteristics of walls of a concert hall wherein the stereophonic signal was originally recorded.
  • the predominant signals derived from speakers 23 and 24 are from the left and right sides of the concert hall.
  • the amplitude of signals derived from the rear speakers 23 and 24 is less than the amplitude of the signals derived from speakers 21 and 22. This is desirable because the listener is usually positioned towards the rear of listening area 25, in greater proximity to rear speakers 23 and 24 than to front speakers 21 and 22.
  • the ratio between the responses of the rear and front speakers can be relatively varied, if desired, by controlling the relative value of resistors in network 28.
  • T network 28 includes three variable resistors 31, 32 and 33 which are provided to control the amplitudes of sounds from front speakers 21 and 22 relative to rear speakers 23 and 24 for a listener positioned towards the rear of the listening area 25.
  • network 28 enables the same amount of negative cross coupling between the left and right channels and speakers 23 and 24.
  • Resistors 31-33 are ganged together so that the values thereof are varied together and are always the same regardless of the direction in which a controller for the values thereof is moved.
  • Resistors 31-33 are increased to attenuate the rear speakers in order for the listener to be able to sit closer to the rear. Without attenuation, and with four loud-speakers of equal efficiency, the listening position is close to the center of the room. If impedance 29 has a value different from the impedance of speakers 23 and 24, the value of resistor 33 is always maintained equal to the value of resistor 31 or 32 times the impedance ratio of impedance 29 to speaker 23 or 24.
  • a monophonic signal is fed to the input terminals of amplifiers l2 and 13.
  • spring biased switch 27 is open circuited and a listener determines if he is able to hear sound from any of the speakers. If speakers 21-24 are balanced, no sound is derived from them because the same signal is applied to each of them and they are connected in a differential pair.
  • the system can be modified by positively blending the left and right channels with +6 db of crossover, as illustrated in FIG. 2.
  • the right and left stereophonic channels derived from source 11, prior to being fed to amplifiers 12 and 13 are fed to a blending network 37 including resistors 38, 39 and 40.
  • Resistors 38 and 39 are respectively connected to the left and right output channels of stereophonic source 11 and the input terminals of amplifiers l2 and 13 while resistor 40 bridges the input terminals of the amplifiers.
  • Each of resistors 38-40 has the same value to provide 6 db of positive crossover between the left and right channels, whereby the output signals of amplifiers 12 and 13 can be respectively represented as (L (It/2)) and (R (L/2)). If the amount of positive crossblending amongst front speakers 21 and 22 is desired to be other than 6 db, the values of resistors 38-39 are changed accordingly.
  • the output signals of amplifiers 12 and 13 are applied directly to the terminals of speakers 21-24 in the same manner as illustrated and described with reference to FIG. 1. In the circuit of FIG.
  • the value of impedance 29 is selected to be four times the impedance of each of speakers 23 and 24, whereby the value of resistor 33 is always four times as great as the value of resistor 31 or 32.
  • the average response of rear speakers 23 and 24 is one-third that of front speakers 21 and 22.
  • the same degree of directivity is derived from rear speakers 23 and 24 as in the embodiment of FIG. 1 because the right and left signals are fed to the speakers with the same relative amplitudes as in the FIG. 1 system.
  • the responses from the front speakers 21 and 22 in the FIG. 2 system provide enhanced directivity. This is because the left and right channel responses are additively combined in speakers 21 and 22.
  • FIG. 3 of the drawings wherein five speakers are interconnected, the fifth speaker 41 performing the function of impedance 29, FIGS. 1 and 2.
  • Comer speakers 21-24 are responsive to the output signals of amplifiers l2 and 13, in the same manner as described in conjunction with either FIG. 1 or FIG. 2.
  • the corner speakers are also positioned as described supra, except that the front corner speakers 21 and 22 may be positioned at a slight acute angle with respect to the front of the listening area.
  • the fifth speaker 41 is connected in circuit in exactly the same manner as impedance 29, FIGS. 1 and 2, and is positioned in close proximity with the front of listening area 25 and approximately midway between the left and right sides of the listening area.
  • Speaker 41 responds to the sum of the currents supplied to rear speakers 23 and 24 and thereby derives a response proportional to the sum of the left and right channels, i.e., proportional to L R. Since the response of speaker 41 is proportional to the sum of the left and right channels, the acoustic output thereof can be considered as similar to the output derived from the front speaker of the diamond array descrived in my aforementioned copending application to simulate the response of a microphone located in the center front of the concert ball.
  • a speaker If a speaker is substituted for impedance 29, it can also be located in a listening area remote from listening area 25, as illustrated in FIG. 4. In such an instance, the four comer speakers can be located in one room, while the fifth speaker 42, FIG. 4, can be located in another room of a dwelling where stereophonic reproduction is not desired. Since speaker 42 is responsive to the sum of the two channels, all of the acoustical information originally in the stereophonic source is reproduced by speaker 42.
  • +6 db of blending for the front speakers and 6 db of blending for the rear speakers is provided by connecting autotransformers 51 and 52 to the output terminals of left and right channel amplifiers l2 and 13,
  • Autotransformers 51 and 52 are designed to have suitable amplitude versus frequency responses over the audio spectrum of interest and include terminals 48 and 49, respectively, connected to the output terminals of amplifiers 12 and 13. Each of autotransformers 51 and 52 includes three equally spaced taps and an unconnected terminal at the other end of a winding from the terminal connected to amplifiers 12 and 13.
  • Center taps 53 and 54 of transformers 51 and 52 are both grounded so that at taps 55 and 56, midway between terminals 48 and 49 and the center taps, there are respectively derived voltages indicative of (+L/2) and (+R/2).
  • front left speaker 21 is connected between the output terminal of amplifier 12 and tap 58 of transformer 52, while the terminals of speaker 22 are connected between the output terminal of amplifier 13 and tap 57 of transformer 51.
  • the voltages thereby applied across speakers 21 and 22 can therefore be respectively written as [L (-R/2)] and [R (L/2)], which can be rewritten as (L (R/2)) and (R (L/2)).
  • the terminals of speaker 23 are connected between the output terminal of amplifier 12 and tap 56 of transformer 52, while right rear speaker 24 is connected between the output terminal of amplifer 13 and tap 55 of transformer 51.
  • Speakers 23 and 24 respond to the voltages applied across their terminals to derive responses respectively proportional to (L (R/2)) and (R (L/ 2)) to establish the desired amount of negative crosscoupling.
  • a transformer arrangement can be employed to provide 6 db of respectively, or crosscoupling for the rear speakers and no crosscoupling for the front speakers by employing the circuit configuration illustrated in FIG. 6.
  • Tapped autotransformers 61 and 62 have the desired amplitude versus frequency characteristics over the audio spectrum to achieve the desired response from the four speakers 21-24.
  • Autotransformers 61 and 62 include center taps 63 and 64, respectively at which are derived voltages U2 and R/2, respectively.
  • speaker 23 To enable speaker 23 to derive an L (R/ 2) output response, its terminals are connected between the output terminal of amplifier 12 and tap 64 of autotransformer 62.
  • the R L/2 response for speaker 24 is obtained by connecting its terminals between the output terminal of amplifier 13 and tap 63 of autotransformer 61.
  • FIG. 7 It may be preferred to drive the systems of FIGS. 1-6 from specially recorded stereophonic signals.
  • the special recording arrangement considered most desirable involves placing microphones effectively at approximately the four corners of a concert hall, as illustrated in FIG. 7.
  • source 71 of acoustic radiation is positioned at the front of the hall and comer microphones 72, 73, 74 and are positioned between source 71 and the rear wall of the hall.
  • Front microphones 72 and 73 are positioned so that their apertures are directed towards the front of the hall in proximity to the left and right edges of source 71.
  • Microphones 74 and 75 which may be located near the rear of the hall, are positioned so their apertures are directed toward the rear of the hall so that they are responsive to ambience and reverberative sounds reflected from the rear wall of the hall.
  • microphones 72-75 With microphones 72-75 positioned approximately in four comers of the hall to transduce acoustic radiation in the manner illustrated by FIG. 7, it is possible to define effective responses for the four walls of the hall in terms of linear combinations of the responses of the four microphones. To this end, assume that the responses of microphones 72, 73, 74 and 75 are respectively denominated as A, B, C and D.
  • the front response can be defined as the sum of the acoustic radiation transduced by microphones 72 and 73, (A B); the left side acoustic energy can be defined as the sum of the acoustic radiation transduced by microphones 72 and 74, (A C); the right side acoustic radiation can be defined as the sum of the acoustic radiation transduced by microphones 73 and 75, (B D); and the rear acoustic energy can be defined as the difference between the acoustic energy transduced by microphones 74 and 75, (C D).
  • the acoustic energy for the rear wall is defined as the difference (C D) because the rear acoustic energy includes ambience information due, e.g., to reflection, reverberation and audience noise, such as applause, which is of random phase and derived with greater accuracy by a differential combination.
  • left and right channels can be formed as if the microphones were located in a diamond array as described in the aforementioned copending application.
  • the left channel of the stereophonic signal can be defined as the acoustic signals transduced from the sum of the left, front and rear of the hall, while the right channel of the stereophonic signal can be defined as the sum of the front and right sounds minus the rear sounds.
  • the left and right channels can therefore be expressed in terms of responses from microphones 72-75 as Equations l and (2), supra.
  • FIG. 8 One system that can be utilized for forming the left and right channel signals is illustrated in FIG. 8. Acoustic signals transduced by microphones 72-75 are fed to amplifiers 76-79, each having an output terminal referenced to ground. The output signals of amplifiers 76-79, which all have the same relative phase as the signals derived by microphones 72-75, are fed to a combining matrix 81. Combining matrix 81 includes eight resistors 82-89, each having the same value. Resistors 82-87 are connected in pairs to form three summing networks that feed input signals to amplifiers 91, 92 and 93.
  • Amplifier 91 responds to the A and B output signals of amplifiers 76 and 77, as coupled through resistors 82 and 83 to derive an (A B) signal indicative of the acoustic radiation at the front of the hall.
  • Amplifier 92 responds to the output signals of amplifiers 76 and 78, as coupled through resistors 84 and 85, to derive an (A C) signal indicative of the left side acoustic radiation.
  • Right side acoustic radiation is derived by amplifier 93 by virtue of the connection of its input terminal to the output terminals of amplifiers 77 and 79 through resistors 86 and 87, respectively.
  • the output terminals of amplifiers 78 and 79 are connected through resistors 88 and 89 to ground and feed plus and minus input terminals of differential amplifier 94.
  • the front, left and back output signals of amplifiers 91, 92 and 94 are additively combined in summing network 95 which derives an output signal in accordance with (l) L 2A B 2C-D.
  • the right channel of the stereophonic signal is derived by additively combining in summing network 97 the output signals of amplifiers 91 and 93 and an inverted replica of the output of amplifier 94, as derived by inverter 96.
  • summing network 97 derives an output signal commensurate with the sum of the responses derived from amplifiers 91 and 93 subtracted from the response of the signal derived at the output terminal of amplifier 94 to produce an output signal in accordance with (2) R A 28 C+ 20, where A sound picked up by a microphone in front left corner;
  • Output device 98 may be a standard two-channel stereophonic device, such as a tape recorder or a stereophonic disc recorder, as well as a stereo f.m. broadcast station.
  • each comer speaker has a response that is predominant for itself and includes components common to the responses of the two speakers with which it is adjacent, but no components in common with the predominant component of the speaker in the opposite comer.
  • speaker 21 in the system of FIG. 2 derives a predominant response associated with the left front corner microphone of the hall illustrated in FIG.
  • Equations (3) (6) it is noted that the response for each corner is devoid of the predominant response of the diagonally opposite comer and includes lower amplitude components for the adjacent comers. In addition, it is noted that the responses for the front speakers are greater than those for the rear speakers, the desired results since the listener is generally in closer proximity to the rear speakers than the front speakers.
  • a balancing network similar to the network illustrated for FIGS. 1-4 can be employed in conjunction with the systems of FIGS. 6 and 7.
  • the six db of positive blending between the right and left channels, as illustrated in the reproduction embodiments of FIGS. 2 and 5 can be obtained by combining the responses of networks and 97 prior to feeding them to putput device 98, FIG. 8.
  • the latter feature in many instances, is not desirable, however, because it is not compatible with standard stereophonic reproduction systems having only two speakers. If the signals derived from summing networks 97 and 95 are directly recorded there is complete compatibility with standard two-speaker stereophonic reproduction systems.
  • the 50 percent cross mixing represented by the factor 1/2, is cancelled by corresponding negative cross feeding in the reproduction system of FIG. 2, popularly known as a Quadaptor (T.M.) This implies that if a front left signal is recorded, no right rear signal will be reproduced, and similarly for a front right signal no left rear signal will be reproduced.
  • T.M. Quadaptor
  • the 50 percent cross feed system of Equations (1) and (2) can be modified in respect to cross feed factor, Le, 50 percent is not critical or essential. It is advantageous to equalize front and back separations, for example, and this can be optimumly accomplished with cross feed 2 Tor 26.8 percent. Separation in both front and rear, apart from outphasing in the rear, is then about 11 db.
  • cross feed 26.8 percent
  • a range of cross feeds should be made available in the recording studio, to provide desired musical effects, and to accomodate various microphone locations and physical recording environments.
  • An audio reproduction system driving four speakers in response to only two left and right stereophonic audio power amplifiers, said amplifiers being left and right amplifiers and the audio signals provided by said amplifiers respectively having audio signal levels denominated as L and R, a different one of said speakers being positioned approximately at each of the four corners of a quadrilateral area, which may be occupied by a listener, said speakers directing sound towards the interior of the area, wherein first and second ones of the speakers are respectively positioned in the left and right rear comers of the area behind the listener and third and fourth ones of the speakers are positioned in the left and right front comers of the area facing the listener, each of said speakers including a signal and a ground terminal, comprising means responsive to said left amplifier for applying a first audio signal to said signal terminals of the front left and rear left speakers, means responsive to the other one of said amplifiers for applying a second audio signal to said signal terminals of the front right and rear right speakers, means grounding the second terminals of the two front speakers, and passive impedance network
  • the impedance network comprises a fifth speaker located at the front of the area approximately midway between the two front speakers.
  • the impedance network comprises a fifth speaker located midway between said front speakers.
  • said impedance network includes first, second and third variable resistors respectively connected, in the order recited, from the rear left speaker, and from the rear right speaker and as a common impedance extending from the first and second variable resistors to ground, and means for gang controlling the values of said resistors so that the first and second resistors always have approximately the same value and the third resistor has a value equal to that of one of the other re sistors multiplied by a predetermined constant.
  • An audio reproduction system driving four speakers in response to only two stereophonic power amplifiers, said amplifiers being respectively denominated as left and right, a different one of said speakers being positioned approximately at each of the four comers of a quadrilateral area, said speakers directing sound towards the interior of the area, wherein first and second ones of the speakers are respectively positioned in the left and right rear comers of the area behind the listener and third and fourth ones of the speakers are positioned in the left and right front comers of the area facing the listener, said speakers each having a signal terminal and a ground terminal, comprising means responsive to one of the amplifiers for applying a first signal to the signal terminals of the front left and rear left comer speakers, means responsive to the other one of the amplifiers for applying an audio signal to the signal terminals of the front right and rear right comer speakers, means grounding the second terminals of the two front speakers, means connected to the second terminals of the two rear speakers for providing a common substantial resistance from the ground terminals of both rear speakers to ground, and means individually
  • An audio reproduction system driving four speakers in response to only left and right power amplifiers, a different one of said speakers being positioned approximately at each of the four corners of a quadrilateral area, said speakers directing sound towards the interior of the area, wherein first and second ones of the speakers are respectively positioned in the left and right rear comers of the area behind the listener and third and fourth ones of the speakers are positioned in the left and right front comers of the area facing the listener, said speakers each having a drive terminal and a ground terminal, comprising means responsive to the left and right amplifiers for deriving responses from the left and right front speakers respectively proportional to the outputs of said amplifiers, means responsive to said left and right amplifiers for deriving audio responses from the left and right rear speakers respectively proportional to (L KR) and (R KL), where K is a constant greater than zero and less than one, L is the output of the left amplifier and R is the output of the right amplifier.
  • the means for deriving responses from the left and right rear speakers comprises a common impedance connecting the ground terminals of only the rear speakers to ground, said common impedance having a value approximately equal to the impedance of one of said rear speakers.
  • An audio reproduction system driving four speakers in response to only two stereophonic amplifiers, said amplifiers being respectively denominated as left and right, a different one of said speakers being positioned approximately at each of the four corners of a quadrilateral area, said speakers directing sound towards the interior of the area, wherein first and second ones of the speakers are respectively positioned in the left and right rear comers of the area behind the lister and third and fourth ones of the speakers are positioned in the left and right front comers of the area facing the listener, comprising means responsive to said amplifiers for deriving responses from the left and right front speakers respectively proportional to (L K R) and (R K,L), means responsive to said amplifiers for deriving responses from the left and right rear speakers respectively proportional to (L K R) and (R K 14), where K, and K are constants greater than 0.25 and less than 0.75, where L is the audio output amplitude of the left amplifier and R is the audio output amplitude of the right amplifier.
  • a four speaker two amplifier stereophonic reproduction system wherein left and right front speakers are connected to left and right amplifiers of said reproduction system, respectively, the combination wherein is provided left and right rear speakers connected respectively to be driven directly by said left and right amplifiers, and a passive circuit connected directly between said rear speakers and ground for introducing at least 25 percent of negative cross coupling of said rear speakers.
  • said loudspeakers being left front, right front, left rear, and right rear loudspeakers, respectively, means connecting said left power amplifier in parallel with the signal output terminals of said left front and left rear loudspeakers, means connecting said right power amplifier in parallel with the signal input terminals of said right front and rear loudspeakers, a switch normally connecting the grounding terminals of said rear loudspeakers to ground, a passive impedance network normally commonly connecting the grounding terminals of said rear speakers to ground via said switch, said impedance network comprising a common resistance connected with said rear speakers in parallel to audibly cross couple said rear loudspeakers.
  • control means for at will disconnecting only said signal input terminals of said rear speakers from said power amplifiers.
  • said impedance network is a resistive T-network including said common resistance and further separate resistances respectively connecting said grounding terminals of said rear speakers to said common resistance and thence via said switch to ground, and a gang control means for commonly adjusting all the resistances of said T-network.
  • a four speaker stereophonic system driven solely from a left and a right power amplifier, said four speakers including left and right front speakers and left and right rear speakers, means driving said left speakers in multiple directly from said left amplifier, means driving said right speakers in multiple directly from said right amplifier, an adjustable resistive passive cross coupling network, said resistive cross coupling network being connected commonly between said rear loudspeakers and ground and providing at least 25 percent cross coupling between said rear loudspeakers.

Landscapes

  • Physics & Mathematics (AREA)
  • Engineering & Computer Science (AREA)
  • Mathematical Physics (AREA)
  • General Physics & Mathematics (AREA)
  • Mathematical Analysis (AREA)
  • Mathematical Optimization (AREA)
  • Algebra (AREA)
  • Pure & Applied Mathematics (AREA)
  • Theoretical Computer Science (AREA)
  • Acoustics & Sound (AREA)
  • Signal Processing (AREA)
  • Stereophonic System (AREA)
  • Circuit For Audible Band Transducer (AREA)
  • Stereophonic Arrangements (AREA)
US151790A 1971-06-10 1971-06-10 Two-channel,four-component stereophonic system Expired - Lifetime US3697692A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US15179071A 1971-06-10 1971-06-10

Publications (1)

Publication Number Publication Date
US3697692A true US3697692A (en) 1972-10-10

Family

ID=22540247

Family Applications (1)

Application Number Title Priority Date Filing Date
US151790A Expired - Lifetime US3697692A (en) 1971-06-10 1971-06-10 Two-channel,four-component stereophonic system

Country Status (6)

Country Link
US (1) US3697692A (enrdf_load_html_response)
JP (1) JPS5119762B1 (enrdf_load_html_response)
DE (1) DE2228274A1 (enrdf_load_html_response)
FR (1) FR2140416A2 (enrdf_load_html_response)
GB (1) GB1367705A (enrdf_load_html_response)
SE (1) SE380418B (enrdf_load_html_response)

Cited By (74)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3725586A (en) * 1971-04-13 1973-04-03 Sony Corp Multisound reproducing apparatus for deriving four sound signals from two sound sources
US3818136A (en) * 1972-04-27 1974-06-18 Zenith Radio Corp Four-channel front-to-back balance control
US3824621A (en) * 1971-06-08 1974-07-16 Tokyo Sanyo Electric Co Multi-channel tape playing device
US3885101A (en) * 1971-12-21 1975-05-20 Sansui Electric Co Signal converting systems for use in stereo reproducing systems
US3889061A (en) * 1971-12-21 1975-06-10 Sansui Electric Co Four-channel reproducing system
US3892917A (en) * 1971-10-07 1975-07-01 Nippon Musical Instruments Mfg Speaker system for multichannel stereosignal reproduction
US3919478A (en) * 1974-01-17 1975-11-11 Zenith Radio Corp Passive four-channel decoder
US3958085A (en) * 1971-09-20 1976-05-18 The Magnavox Company Compatible 4-2-4 encoding-decoding system
US4002835A (en) * 1975-06-06 1977-01-11 Bumber Roger L Multi-channel decoding circuit for two-channel audio systems
US4034158A (en) * 1972-12-05 1977-07-05 Britton Berdette O Quadraphonic passive four-channel decoder
US4097688A (en) * 1970-11-16 1978-06-27 Matsushita Electric Industrial Co., Ltd. Stereophonic reproducing system
US4132859A (en) * 1977-12-02 1979-01-02 Egils Ranga Sound reproducing apparatus
US4308423A (en) * 1980-03-12 1981-12-29 Cohen Joel M Stereo image separation and perimeter enhancement
US4355203A (en) * 1980-03-12 1982-10-19 Cohen Joel M Stereo image separation and perimeter enhancement
US4443889A (en) * 1980-04-21 1984-04-17 Nortech Laboratories Ltd. Acoustic apparatus and method
US4489432A (en) * 1982-05-28 1984-12-18 Polk Audio, Inc. Method and apparatus for reproducing sound having a realistic ambient field and acoustic image
US4497064A (en) * 1982-08-05 1985-01-29 Polk Audio, Inc. Method and apparatus for reproducing sound having an expanded acoustic image
DE3519644A1 (de) * 1984-06-01 1985-12-05 Polk Audio, Inc., Baltimore, Md. Verfahren und vorrichtung zur tonwiedergabe mit einem realistischen raumklangeindruck
US4612663A (en) * 1984-03-26 1986-09-16 Holbrook Kyle A Multichannel audio reproduction system
US4759066A (en) * 1987-05-27 1988-07-19 Polk Investment Corporation Sound system with isolation of dimensional sub-speakers
US4819269A (en) * 1987-07-21 1989-04-04 Hughes Aircraft Company Extended imaging split mode loudspeaker system
US4837825A (en) * 1987-02-28 1989-06-06 Shivers Clarence L Passive ambience recovery system for the reproduction of sound
US4882753A (en) * 1988-01-19 1989-11-21 Shivers Clarence L Passive ambience recovery system for the reproduction of sound
DE3932984A1 (de) * 1989-01-24 1990-07-26 Pioneer Electronic Corp Rundum-stereo-audiowiedergabeeinrichtung
EP0442388A1 (de) * 1990-02-12 1991-08-21 Georg Diamantidis Schaltungsanordnung zur Modifikation der Ausgangssignale eines mehrkanaligen elektroakustischen Geräts
US5386473A (en) * 1994-01-21 1995-01-31 Harrison; Robert W. Passive surround sound circuit
US5412731A (en) * 1982-11-08 1995-05-02 Desper Products, Inc. Automatic stereophonic manipulation system and apparatus for image enhancement
US5497425A (en) * 1994-03-07 1996-03-05 Rapoport; Robert J. Multi channel surround sound simulation device
US5594801A (en) * 1994-05-26 1997-01-14 Mcshane; Charles L. Ambient expansion loudspeaker system
US5594800A (en) * 1991-02-15 1997-01-14 Trifield Productions Limited Sound reproduction system having a matrix converter
US5598480A (en) * 1994-11-07 1997-01-28 Kim; Man H. Multiple output transformer network for sound reproducing system
US5661808A (en) * 1995-04-27 1997-08-26 Srs Labs, Inc. Stereo enhancement system
US5666422A (en) * 1994-05-18 1997-09-09 Harrison; Robert W. Remote speaker for surround-sound applications
US5677957A (en) * 1995-11-13 1997-10-14 Hulsebus; Alan Audio circuit producing enhanced ambience
US5708719A (en) * 1995-09-07 1998-01-13 Rep Investment Limited Liability Company In-home theater surround sound speaker system
US5742691A (en) * 1997-02-21 1998-04-21 Ambourn; Paul R. Surround sound converter
US5841879A (en) * 1996-11-21 1998-11-24 Sonics Associates, Inc. Virtually positioned head mounted surround sound system
US5850453A (en) * 1995-07-28 1998-12-15 Srs Labs, Inc. Acoustic correction apparatus
US5912976A (en) * 1996-11-07 1999-06-15 Srs Labs, Inc. Multi-channel audio enhancement system for use in recording and playback and methods for providing same
US5930370A (en) * 1995-09-07 1999-07-27 Rep Investment Limited Liability In-home theater surround sound speaker system
US5970152A (en) * 1996-04-30 1999-10-19 Srs Labs, Inc. Audio enhancement system for use in a surround sound environment
US6118876A (en) * 1995-09-07 2000-09-12 Rep Investment Limited Liability Company Surround sound speaker system for improved spatial effects
US6144747A (en) * 1997-04-02 2000-11-07 Sonics Associates, Inc. Head mounted surround sound system
US6163613A (en) * 1995-06-26 2000-12-19 Cowans; Kenneth W. Low-distortion loudspeaker
US6281749B1 (en) 1997-06-17 2001-08-28 Srs Labs, Inc. Sound enhancement system
US20020015505A1 (en) * 2000-06-12 2002-02-07 Katz Robert A. Process for enhancing the existing ambience, imaging, depth, clarity and spaciousness of sound recordings
US20030063761A1 (en) * 2001-09-28 2003-04-03 Audio Products International Corp. System for distributing a signal between loudspeaker drivers
US20050071028A1 (en) * 1999-12-10 2005-03-31 Yuen Thomas C.K. System and method for enhanced streaming audio
US20050152556A1 (en) * 2004-01-09 2005-07-14 Masonware Partners Llc Passive surround sound adapter
US7031474B1 (en) 1999-10-04 2006-04-18 Srs Labs, Inc. Acoustic correction apparatus
US7184723B2 (en) 2004-10-22 2007-02-27 Parkervision, Inc. Systems and methods for vector power amplification
US7355470B2 (en) 2006-04-24 2008-04-08 Parkervision, Inc. Systems and methods of RF power transmission, modulation, and amplification, including embodiments for amplifier class transitioning
US7567845B1 (en) * 2002-06-04 2009-07-28 Creative Technology Ltd Ambience generation for stereo signals
US7620129B2 (en) 2007-01-16 2009-11-17 Parkervision, Inc. RF power transmission, modulation, and amplification, including embodiments for generating vector modulation control signals
US20100296657A1 (en) * 2007-11-23 2010-11-25 Chung Won Sup Apparatus for sound having multiples stereo imaging
US7885682B2 (en) 2006-04-24 2011-02-08 Parkervision, Inc. Systems and methods of RF power transmission, modulation, and amplification, including architectural embodiments of same
US7911272B2 (en) 2007-06-19 2011-03-22 Parkervision, Inc. Systems and methods of RF power transmission, modulation, and amplification, including blended control embodiments
US7970144B1 (en) 2003-12-17 2011-06-28 Creative Technology Ltd Extracting and modifying a panned source for enhancement and upmix of audio signals
US8013675B2 (en) 2007-06-19 2011-09-06 Parkervision, Inc. Combiner-less multiple input single output (MISO) amplification with blended control
US8031804B2 (en) 2006-04-24 2011-10-04 Parkervision, Inc. Systems and methods of RF tower transmission, modulation, and amplification, including embodiments for compensating for waveform distortion
US8050434B1 (en) 2006-12-21 2011-11-01 Srs Labs, Inc. Multi-channel audio enhancement system
US20120221329A1 (en) * 2009-10-27 2012-08-30 Phonak Ag Speech enhancement method and system
US8315336B2 (en) 2007-05-18 2012-11-20 Parkervision, Inc. Systems and methods of RF power transmission, modulation, and amplification, including a switching stage embodiment
US8334722B2 (en) 2007-06-28 2012-12-18 Parkervision, Inc. Systems and methods of RF power transmission, modulation and amplification
US8755454B2 (en) 2011-06-02 2014-06-17 Parkervision, Inc. Antenna control
US9084047B2 (en) 2013-03-15 2015-07-14 Richard O'Polka Portable sound system
US9088858B2 (en) 2011-01-04 2015-07-21 Dts Llc Immersive audio rendering system
US9106316B2 (en) 2005-10-24 2015-08-11 Parkervision, Inc. Systems and methods of RF power transmission, modulation, and amplification
USD740784S1 (en) 2014-03-14 2015-10-13 Richard O'Polka Portable sound device
US9258664B2 (en) 2013-05-23 2016-02-09 Comhear, Inc. Headphone audio enhancement system
US9608677B2 (en) 2005-10-24 2017-03-28 Parker Vision, Inc Systems and methods of RF power transmission, modulation, and amplification
US9998244B2 (en) 2012-07-24 2018-06-12 Fox Filmed Entertainment Method and apparatus for mixing event driven media
US10149058B2 (en) 2013-03-15 2018-12-04 Richard O'Polka Portable sound system
US10278131B2 (en) 2013-09-17 2019-04-30 Parkervision, Inc. Method, apparatus and system for rendering an information bearing function of time

Families Citing this family (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
AT379275B (de) * 1982-04-20 1985-12-10 Neutrik Ag Stereophone wiedergabeanlage in fahrgastraeumen von kraftfahrzeugen
US5034983A (en) * 1987-10-15 1991-07-23 Cooper Duane H Head diffraction compensated stereo system
US5136651A (en) * 1987-10-15 1992-08-04 Cooper Duane H Head diffraction compensated stereo system
US4910779A (en) * 1987-10-15 1990-03-20 Cooper Duane H Head diffraction compensated stereo system with optimal equalization
US4975954A (en) * 1987-10-15 1990-12-04 Cooper Duane H Head diffraction compensated stereo system with optimal equalization

Family Cites Families (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS4932325A (enrdf_load_html_response) * 1972-07-27 1974-03-25

Cited By (158)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4097688A (en) * 1970-11-16 1978-06-27 Matsushita Electric Industrial Co., Ltd. Stereophonic reproducing system
US3725586A (en) * 1971-04-13 1973-04-03 Sony Corp Multisound reproducing apparatus for deriving four sound signals from two sound sources
US3824621A (en) * 1971-06-08 1974-07-16 Tokyo Sanyo Electric Co Multi-channel tape playing device
US3958085A (en) * 1971-09-20 1976-05-18 The Magnavox Company Compatible 4-2-4 encoding-decoding system
US3892917A (en) * 1971-10-07 1975-07-01 Nippon Musical Instruments Mfg Speaker system for multichannel stereosignal reproduction
US3885101A (en) * 1971-12-21 1975-05-20 Sansui Electric Co Signal converting systems for use in stereo reproducing systems
US3889061A (en) * 1971-12-21 1975-06-10 Sansui Electric Co Four-channel reproducing system
US3818136A (en) * 1972-04-27 1974-06-18 Zenith Radio Corp Four-channel front-to-back balance control
US4034158A (en) * 1972-12-05 1977-07-05 Britton Berdette O Quadraphonic passive four-channel decoder
US3919478A (en) * 1974-01-17 1975-11-11 Zenith Radio Corp Passive four-channel decoder
US4002835A (en) * 1975-06-06 1977-01-11 Bumber Roger L Multi-channel decoding circuit for two-channel audio systems
US4132859A (en) * 1977-12-02 1979-01-02 Egils Ranga Sound reproducing apparatus
US4308423A (en) * 1980-03-12 1981-12-29 Cohen Joel M Stereo image separation and perimeter enhancement
US4355203A (en) * 1980-03-12 1982-10-19 Cohen Joel M Stereo image separation and perimeter enhancement
US4443889A (en) * 1980-04-21 1984-04-17 Nortech Laboratories Ltd. Acoustic apparatus and method
US4489432A (en) * 1982-05-28 1984-12-18 Polk Audio, Inc. Method and apparatus for reproducing sound having a realistic ambient field and acoustic image
US4497064A (en) * 1982-08-05 1985-01-29 Polk Audio, Inc. Method and apparatus for reproducing sound having an expanded acoustic image
US5412731A (en) * 1982-11-08 1995-05-02 Desper Products, Inc. Automatic stereophonic manipulation system and apparatus for image enhancement
US4612663A (en) * 1984-03-26 1986-09-16 Holbrook Kyle A Multichannel audio reproduction system
DE3519644A1 (de) * 1984-06-01 1985-12-05 Polk Audio, Inc., Baltimore, Md. Verfahren und vorrichtung zur tonwiedergabe mit einem realistischen raumklangeindruck
US4837825A (en) * 1987-02-28 1989-06-06 Shivers Clarence L Passive ambience recovery system for the reproduction of sound
US4759066A (en) * 1987-05-27 1988-07-19 Polk Investment Corporation Sound system with isolation of dimensional sub-speakers
US4819269A (en) * 1987-07-21 1989-04-04 Hughes Aircraft Company Extended imaging split mode loudspeaker system
US4882753A (en) * 1988-01-19 1989-11-21 Shivers Clarence L Passive ambience recovery system for the reproduction of sound
US4953213A (en) * 1989-01-24 1990-08-28 Pioneer Electronic Corporation Surround mode stereophonic reproducing equipment
DE3932984A1 (de) * 1989-01-24 1990-07-26 Pioneer Electronic Corp Rundum-stereo-audiowiedergabeeinrichtung
WO1991012699A1 (de) * 1990-02-12 1991-08-22 Georg Diamantidis Schaltungsanordnung zur modifikation der ausgangssignale eines mehrkanaligen elektroakustischen geräts
EP0442388A1 (de) * 1990-02-12 1991-08-21 Georg Diamantidis Schaltungsanordnung zur Modifikation der Ausgangssignale eines mehrkanaligen elektroakustischen Geräts
US5594800A (en) * 1991-02-15 1997-01-14 Trifield Productions Limited Sound reproduction system having a matrix converter
US5386473A (en) * 1994-01-21 1995-01-31 Harrison; Robert W. Passive surround sound circuit
US5497425A (en) * 1994-03-07 1996-03-05 Rapoport; Robert J. Multi channel surround sound simulation device
US5666422A (en) * 1994-05-18 1997-09-09 Harrison; Robert W. Remote speaker for surround-sound applications
US5594801A (en) * 1994-05-26 1997-01-14 Mcshane; Charles L. Ambient expansion loudspeaker system
US5598480A (en) * 1994-11-07 1997-01-28 Kim; Man H. Multiple output transformer network for sound reproducing system
US5892830A (en) * 1995-04-27 1999-04-06 Srs Labs, Inc. Stereo enhancement system
US6597791B1 (en) 1995-04-27 2003-07-22 Srs Labs, Inc. Audio enhancement system
US20040005063A1 (en) * 1995-04-27 2004-01-08 Klayman Arnold I. Audio enhancement system
US7636443B2 (en) 1995-04-27 2009-12-22 Srs Labs, Inc. Audio enhancement system
US5661808A (en) * 1995-04-27 1997-08-26 Srs Labs, Inc. Stereo enhancement system
US6163613A (en) * 1995-06-26 2000-12-19 Cowans; Kenneth W. Low-distortion loudspeaker
US7043031B2 (en) 1995-07-28 2006-05-09 Srs Labs, Inc. Acoustic correction apparatus
US7555130B2 (en) 1995-07-28 2009-06-30 Srs Labs, Inc. Acoustic correction apparatus
US20060062395A1 (en) * 1995-07-28 2006-03-23 Klayman Arnold I Acoustic correction apparatus
US6718039B1 (en) 1995-07-28 2004-04-06 Srs Labs, Inc. Acoustic correction apparatus
US5850453A (en) * 1995-07-28 1998-12-15 Srs Labs, Inc. Acoustic correction apparatus
US5930370A (en) * 1995-09-07 1999-07-27 Rep Investment Limited Liability In-home theater surround sound speaker system
US6118876A (en) * 1995-09-07 2000-09-12 Rep Investment Limited Liability Company Surround sound speaker system for improved spatial effects
US5708719A (en) * 1995-09-07 1998-01-13 Rep Investment Limited Liability Company In-home theater surround sound speaker system
US5677957A (en) * 1995-11-13 1997-10-14 Hulsebus; Alan Audio circuit producing enhanced ambience
US5970152A (en) * 1996-04-30 1999-10-19 Srs Labs, Inc. Audio enhancement system for use in a surround sound environment
US7200236B1 (en) 1996-11-07 2007-04-03 Srslabs, Inc. Multi-channel audio enhancement system for use in recording playback and methods for providing same
US20090190766A1 (en) * 1996-11-07 2009-07-30 Srs Labs, Inc. Multi-channel audio enhancement system for use in recording playback and methods for providing same
US7492907B2 (en) 1996-11-07 2009-02-17 Srs Labs, Inc. Multi-channel audio enhancement system for use in recording and playback and methods for providing same
US8472631B2 (en) 1996-11-07 2013-06-25 Dts Llc Multi-channel audio enhancement system for use in recording playback and methods for providing same
US5912976A (en) * 1996-11-07 1999-06-15 Srs Labs, Inc. Multi-channel audio enhancement system for use in recording and playback and methods for providing same
US5841879A (en) * 1996-11-21 1998-11-24 Sonics Associates, Inc. Virtually positioned head mounted surround sound system
US5742691A (en) * 1997-02-21 1998-04-21 Ambourn; Paul R. Surround sound converter
US6144747A (en) * 1997-04-02 2000-11-07 Sonics Associates, Inc. Head mounted surround sound system
US6281749B1 (en) 1997-06-17 2001-08-28 Srs Labs, Inc. Sound enhancement system
US7907736B2 (en) 1999-10-04 2011-03-15 Srs Labs, Inc. Acoustic correction apparatus
US7031474B1 (en) 1999-10-04 2006-04-18 Srs Labs, Inc. Acoustic correction apparatus
US8751028B2 (en) 1999-12-10 2014-06-10 Dts Llc System and method for enhanced streaming audio
US7277767B2 (en) 1999-12-10 2007-10-02 Srs Labs, Inc. System and method for enhanced streaming audio
US8046093B2 (en) 1999-12-10 2011-10-25 Srs Labs, Inc. System and method for enhanced streaming audio
US7987281B2 (en) 1999-12-10 2011-07-26 Srs Labs, Inc. System and method for enhanced streaming audio
US7467021B2 (en) 1999-12-10 2008-12-16 Srs Labs, Inc. System and method for enhanced streaming audio
US20050071028A1 (en) * 1999-12-10 2005-03-31 Yuen Thomas C.K. System and method for enhanced streaming audio
US20090094519A1 (en) * 1999-12-10 2009-04-09 Srs Labs, Inc. System and method for enhanced streaming audio
US7076071B2 (en) 2000-06-12 2006-07-11 Robert A. Katz Process for enhancing the existing ambience, imaging, depth, clarity and spaciousness of sound recordings
US20020015505A1 (en) * 2000-06-12 2002-02-07 Katz Robert A. Process for enhancing the existing ambience, imaging, depth, clarity and spaciousness of sound recordings
US20030063761A1 (en) * 2001-09-28 2003-04-03 Audio Products International Corp. System for distributing a signal between loudspeaker drivers
US6993141B2 (en) * 2001-09-28 2006-01-31 Audio Products International Corp. System for distributing a signal between loudspeaker drivers
US7567845B1 (en) * 2002-06-04 2009-07-28 Creative Technology Ltd Ambience generation for stereo signals
US7970144B1 (en) 2003-12-17 2011-06-28 Creative Technology Ltd Extracting and modifying a panned source for enhancement and upmix of audio signals
US20050152556A1 (en) * 2004-01-09 2005-07-14 Masonware Partners Llc Passive surround sound adapter
US7639072B2 (en) 2004-10-22 2009-12-29 Parkervision, Inc. Controlling a power amplifier to transition among amplifier operational classes according to at least an output signal waveform trajectory
US8639196B2 (en) 2004-10-22 2014-01-28 Parkervision, Inc. Control modules
US9768733B2 (en) 2004-10-22 2017-09-19 Parker Vision, Inc. Multiple input single output device with vector signal and bias signal inputs
US7466760B2 (en) 2004-10-22 2008-12-16 Parkervision, Inc. Systems and methods of RF power transmission, modulation, and amplification, including transfer function embodiments
US8351870B2 (en) 2004-10-22 2013-01-08 Parkervision, Inc. Systems and methods of RF power transmission, modulation, and amplification, including cartesian 4-branch embodiments
US7647030B2 (en) 2004-10-22 2010-01-12 Parkervision, Inc. Multiple input single output (MISO) amplifier with circuit branch output tracking
US7672650B2 (en) 2004-10-22 2010-03-02 Parkervision, Inc. Systems and methods of RF power transmission, modulation, and amplification, including multiple input single output (MISO) amplifier embodiments comprising harmonic control circuitry
US8428527B2 (en) 2004-10-22 2013-04-23 Parkervision, Inc. RF power transmission, modulation, and amplification, including direct cartesian 2-branch embodiments
US7835709B2 (en) 2004-10-22 2010-11-16 Parkervision, Inc. RF power transmission, modulation, and amplification using multiple input single output (MISO) amplifiers to process phase angle and magnitude information
US8433264B2 (en) 2004-10-22 2013-04-30 Parkervision, Inc. Multiple input single output (MISO) amplifier having multiple transistors whose output voltages substantially equal the amplifier output voltage
US7844235B2 (en) 2004-10-22 2010-11-30 Parkervision, Inc. RF power transmission, modulation, and amplification, including harmonic control embodiments
US8280321B2 (en) 2004-10-22 2012-10-02 Parkervision, Inc. Systems and methods of RF power transmission, modulation, and amplification, including Cartesian-Polar-Cartesian-Polar (CPCP) embodiments
US7421036B2 (en) 2004-10-22 2008-09-02 Parkervision, Inc. Systems and methods of RF power transmission, modulation, and amplification, including transfer function embodiments
US9197164B2 (en) 2004-10-22 2015-11-24 Parkervision, Inc. RF power transmission, modulation, and amplification, including direct cartesian 2-branch embodiments
US9197163B2 (en) 2004-10-22 2015-11-24 Parkvision, Inc. Systems, and methods of RF power transmission, modulation, and amplification, including embodiments for output stage protection
US7932776B2 (en) 2004-10-22 2011-04-26 Parkervision, Inc. RF power transmission, modulation, and amplification embodiments
US9166528B2 (en) 2004-10-22 2015-10-20 Parkervision, Inc. RF power transmission, modulation, and amplification embodiments
US7945224B2 (en) 2004-10-22 2011-05-17 Parkervision, Inc. Systems and methods of RF power transmission, modulation, and amplification, including waveform distortion compensation embodiments
US9143088B2 (en) 2004-10-22 2015-09-22 Parkervision, Inc. Control modules
US8447248B2 (en) 2004-10-22 2013-05-21 Parkervision, Inc. RF power transmission, modulation, and amplification, including power control of multiple input single output (MISO) amplifiers
US8233858B2 (en) 2004-10-22 2012-07-31 Parkervision, Inc. RF power transmission, modulation, and amplification embodiments, including control circuitry for controlling power amplifier output stages
US8913974B2 (en) 2004-10-22 2014-12-16 Parkervision, Inc. RF power transmission, modulation, and amplification, including direct cartesian 2-branch embodiments
US7526261B2 (en) 2004-10-22 2009-04-28 Parkervision, Inc. RF power transmission, modulation, and amplification, including cartesian 4-branch embodiments
US8781418B2 (en) 2004-10-22 2014-07-15 Parkervision, Inc. Power amplification based on phase angle controlled reference signal and amplitude control signal
US7184723B2 (en) 2004-10-22 2007-02-27 Parkervision, Inc. Systems and methods for vector power amplification
US8406711B2 (en) 2004-10-22 2013-03-26 Parkervision, Inc. Systems and methods of RF power transmission, modulation, and amplification, including a Cartesian-Polar-Cartesian-Polar (CPCP) embodiment
US8626093B2 (en) 2004-10-22 2014-01-07 Parkervision, Inc. RF power transmission, modulation, and amplification embodiments
US8577313B2 (en) 2004-10-22 2013-11-05 Parkervision, Inc. Systems and methods of RF power transmission, modulation, and amplification, including output stage protection circuitry
US7327803B2 (en) 2004-10-22 2008-02-05 Parkervision, Inc. Systems and methods for vector power amplification
US9094085B2 (en) 2005-10-24 2015-07-28 Parkervision, Inc. Control of MISO node
US9106316B2 (en) 2005-10-24 2015-08-11 Parkervision, Inc. Systems and methods of RF power transmission, modulation, and amplification
US9419692B2 (en) 2005-10-24 2016-08-16 Parkervision, Inc. Antenna control
US9608677B2 (en) 2005-10-24 2017-03-28 Parker Vision, Inc Systems and methods of RF power transmission, modulation, and amplification
US9614484B2 (en) 2005-10-24 2017-04-04 Parkervision, Inc. Systems and methods of RF power transmission, modulation, and amplification, including control functions to transition an output of a MISO device
US9705540B2 (en) 2005-10-24 2017-07-11 Parker Vision, Inc. Control of MISO node
US8026764B2 (en) 2006-04-24 2011-09-27 Parkervision, Inc. Generation and amplification of substantially constant envelope signals, including switching an output among a plurality of nodes
US7414469B2 (en) 2006-04-24 2008-08-19 Parkervision, Inc. Systems and methods of RF power transmission, modulation, and amplification, including embodiments for amplifier class transitioning
US7929989B2 (en) 2006-04-24 2011-04-19 Parkervision, Inc. Systems and methods of RF power transmission, modulation, and amplification, including architectural embodiments of same
US7937106B2 (en) 2006-04-24 2011-05-03 ParkerVision, Inc, Systems and methods of RF power transmission, modulation, and amplification, including architectural embodiments of same
US7750733B2 (en) 2006-04-24 2010-07-06 Parkervision, Inc. Systems and methods of RF power transmission, modulation, and amplification, including embodiments for extending RF transmission bandwidth
US7949365B2 (en) 2006-04-24 2011-05-24 Parkervision, Inc. Systems and methods of RF power transmission, modulation, and amplification, including architectural embodiments of same
US8059749B2 (en) 2006-04-24 2011-11-15 Parkervision, Inc. Systems and methods of RF power transmission, modulation, and amplification, including embodiments for compensating for waveform distortion
US9106500B2 (en) 2006-04-24 2015-08-11 Parkervision, Inc. Systems and methods of RF power transmission, modulation, and amplification, including embodiments for error correction
US7885682B2 (en) 2006-04-24 2011-02-08 Parkervision, Inc. Systems and methods of RF power transmission, modulation, and amplification, including architectural embodiments of same
US7378902B2 (en) 2006-04-24 2008-05-27 Parkervision, Inc Systems and methods of RF power transmission, modulation, and amplification, including embodiments for gain and phase control
US7423477B2 (en) 2006-04-24 2008-09-09 Parkervision, Inc. Systems and methods of RF power transmission, modulation, and amplification, including embodiments for amplifier class transitioning
US8050353B2 (en) 2006-04-24 2011-11-01 Parkervision, Inc. Systems and methods of RF power transmission, modulation, and amplification, including embodiments for compensating for waveform distortion
US8031804B2 (en) 2006-04-24 2011-10-04 Parkervision, Inc. Systems and methods of RF tower transmission, modulation, and amplification, including embodiments for compensating for waveform distortion
US7355470B2 (en) 2006-04-24 2008-04-08 Parkervision, Inc. Systems and methods of RF power transmission, modulation, and amplification, including embodiments for amplifier class transitioning
US8036306B2 (en) 2006-04-24 2011-10-11 Parkervision, Inc. Systems and methods of RF power transmission, modulation and amplification, including embodiments for compensating for waveform distortion
US8913691B2 (en) 2006-08-24 2014-12-16 Parkervision, Inc. Controlling output power of multiple-input single-output (MISO) device
US9232312B2 (en) 2006-12-21 2016-01-05 Dts Llc Multi-channel audio enhancement system
US8050434B1 (en) 2006-12-21 2011-11-01 Srs Labs, Inc. Multi-channel audio enhancement system
US8509464B1 (en) 2006-12-21 2013-08-13 Dts Llc Multi-channel audio enhancement system
US7620129B2 (en) 2007-01-16 2009-11-17 Parkervision, Inc. RF power transmission, modulation, and amplification, including embodiments for generating vector modulation control signals
US8548093B2 (en) 2007-05-18 2013-10-01 Parkervision, Inc. Power amplification based on frequency control signal
US8315336B2 (en) 2007-05-18 2012-11-20 Parkervision, Inc. Systems and methods of RF power transmission, modulation, and amplification, including a switching stage embodiment
US8461924B2 (en) 2007-06-19 2013-06-11 Parkervision, Inc. Systems and methods of RF power transmission, modulation, and amplification, including embodiments for controlling a transimpedance node
US8410849B2 (en) 2007-06-19 2013-04-02 Parkervision, Inc. Systems and methods of RF power transmission, modulation, and amplification, including blended control embodiments
US8013675B2 (en) 2007-06-19 2011-09-06 Parkervision, Inc. Combiner-less multiple input single output (MISO) amplification with blended control
US8502600B2 (en) 2007-06-19 2013-08-06 Parkervision, Inc. Combiner-less multiple input single output (MISO) amplification with blended control
US7911272B2 (en) 2007-06-19 2011-03-22 Parkervision, Inc. Systems and methods of RF power transmission, modulation, and amplification, including blended control embodiments
US8766717B2 (en) 2007-06-19 2014-07-01 Parkervision, Inc. Systems and methods of RF power transmission, modulation, and amplification, including varying weights of control signals
US8884694B2 (en) 2007-06-28 2014-11-11 Parkervision, Inc. Systems and methods of RF power transmission, modulation, and amplification
US8334722B2 (en) 2007-06-28 2012-12-18 Parkervision, Inc. Systems and methods of RF power transmission, modulation and amplification
US8559644B2 (en) * 2007-11-23 2013-10-15 Won Sup Chung Apparatus for sound having multiples stereo imaging
US20100296657A1 (en) * 2007-11-23 2010-11-25 Chung Won Sup Apparatus for sound having multiples stereo imaging
US20120221329A1 (en) * 2009-10-27 2012-08-30 Phonak Ag Speech enhancement method and system
US8831934B2 (en) * 2009-10-27 2014-09-09 Phonak Ag Speech enhancement method and system
US9088858B2 (en) 2011-01-04 2015-07-21 Dts Llc Immersive audio rendering system
US10034113B2 (en) 2011-01-04 2018-07-24 Dts Llc Immersive audio rendering system
US9154897B2 (en) 2011-01-04 2015-10-06 Dts Llc Immersive audio rendering system
US8755454B2 (en) 2011-06-02 2014-06-17 Parkervision, Inc. Antenna control
US9998244B2 (en) 2012-07-24 2018-06-12 Fox Filmed Entertainment Method and apparatus for mixing event driven media
US10149058B2 (en) 2013-03-15 2018-12-04 Richard O'Polka Portable sound system
US9084047B2 (en) 2013-03-15 2015-07-14 Richard O'Polka Portable sound system
US9560442B2 (en) 2013-03-15 2017-01-31 Richard O'Polka Portable sound system
US10771897B2 (en) 2013-03-15 2020-09-08 Richard O'Polka Portable sound system
US9866963B2 (en) 2013-05-23 2018-01-09 Comhear, Inc. Headphone audio enhancement system
US9258664B2 (en) 2013-05-23 2016-02-09 Comhear, Inc. Headphone audio enhancement system
US10284955B2 (en) 2013-05-23 2019-05-07 Comhear, Inc. Headphone audio enhancement system
US10278131B2 (en) 2013-09-17 2019-04-30 Parkervision, Inc. Method, apparatus and system for rendering an information bearing function of time
USD740784S1 (en) 2014-03-14 2015-10-13 Richard O'Polka Portable sound device

Also Published As

Publication number Publication date
FR2140416A2 (enrdf_load_html_response) 1973-01-19
DE2228274A1 (de) 1972-12-28
GB1367705A (en) 1974-09-18
SE380418B (sv) 1975-11-03
JPS5119762B1 (enrdf_load_html_response) 1976-06-19

Similar Documents

Publication Publication Date Title
US3697692A (en) Two-channel,four-component stereophonic system
US3746792A (en) Multidirectional sound system
US5555306A (en) Audio signal processor providing simulated source distance control
US3632886A (en) Quadrasonic sound system
US4219696A (en) Sound image localization control system
US5386473A (en) Passive surround sound circuit
US5610986A (en) Linear-matrix audio-imaging system and image analyzer
US3892624A (en) Stereophonic sound reproducing system
US5043970A (en) Sound system with source material and surround timbre response correction, specified front and surround loudspeaker directionality, and multi-loudspeaker surround
US3757047A (en) Four channel sound reproduction system
US5497425A (en) Multi channel surround sound simulation device
US8571232B2 (en) Apparatus and method for a complete audio signal
US5222059A (en) Surround-sound system with motion picture soundtrack timbre correction, surround sound channel timbre correction, defined loudspeaker directionality, and reduced comb-filter effects
US5119422A (en) Optimal sonic separator and multi-channel forward imaging system
US4132859A (en) Sound reproducing apparatus
US20110064230A1 (en) Phase layering apparatus and method for a complete audio signal
US3941931A (en) Audio signal mixing system
US3417203A (en) Two-channel stereo system with derived center channel
US3821471A (en) Apparatus for reproducing quadraphonic sound
US3798373A (en) Apparatus for reproducing quadraphonic sound
US3835255A (en) Matrix decoders for quadraphonic sound system
US4002835A (en) Multi-channel decoding circuit for two-channel audio systems
US4352953A (en) Multichannel non-discrete audio reproduction system
US4394535A (en) Split phase stereophonic sound synthesizer
US3818136A (en) Four-channel front-to-back balance control