US3754099A - Four channel stereophonic broadcasting system - Google Patents

Four channel stereophonic broadcasting system Download PDF

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Publication number
US3754099A
US3754099A US00196932A US3754099DA US3754099A US 3754099 A US3754099 A US 3754099A US 00196932 A US00196932 A US 00196932A US 3754099D A US3754099D A US 3754099DA US 3754099 A US3754099 A US 3754099A
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Prior art keywords
signal
bandwidth
modulated
composite
signals
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Expired - Lifetime
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US00196932A
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English (en)
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S Takaoka
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Pioneer Corp
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Pioneer Electronic Corp
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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
    • H04H20/89—Stereophonic broadcast systems using three or more audio channels, e.g. triphonic or quadraphonic

Definitions

  • ABSTRACT A broadcasting system wherein a left front, a right front, a left rear, and a right rear signal are transmitted on a single radio frequency channel with no significant increase in bandwidth. It should be compatible, that is, it should give satisfactory monophonic and two channel stereophonic reception on receivers presently in use by the public.
  • the invention relates to systems for the transmission of multiplex signals and particularly to systems for the transmission of four channel stereophonic signals by means of frequency modulation broadcasting, and to transmitters and receivers for use in such systems.
  • the FM multiplex stereophonic broadcasting system which has been adopted in Japan and is called the pilot tone system, transmits a left (or L) channel signal and a right (or R) channel signal on a single radio frequency channel and converts the signals with a receiver into L and R signals to achieve two channel stereophonic reproduction.
  • the pilot tone system transmits a left (or L) channel signal and a right (or R) channel signal on a single radio frequency channel and converts the signals with a receiver into L and R signals to achieve two channel stereophonic reproduction.
  • the main factors which are desirable in such a four channel system can be summarized as follows: it should be compatible, that is, it should give'satisfactory monophonic and two channel stereophonic reception on receivers presently in use by the public; it should give quality equal to present systems in frequency characteristic, distortion factor, signal-to-noise ratio and other characteristics; and it should be capable of transmission of a composite signal on about 100 KHZ or less with no significant increase in bandwidth.
  • FIG. 1 is an electrical block diagram of a preferred embodiment of a transmitter in accordance with the invention, and also graphical represen-tations of frequency relationships of signals used in carrying out the invention.
  • FIG. 2 is an electrical block diagram of a preferred embodiment of a receiver in accordance with the invention.
  • a signal source 1 1 produces a signal representing a left front (or LP) channel, a signal representing a right front (or RF) channel, a signal representing a left rear (or LR) channel and a signal representing a right rear (or RR) channel.
  • these signals are added or subtracted to obtain an (LF LR) signal, an (RF RR) signal, an (LF LR) signal and an (RF RR) signal.
  • an (LF LR) (RF RR) signal (hereinafter being called only A" signal for simplicity), an (LF LR) (RF RR) signal (3" signal), an (LF LR) (RF RR) signal (C signal) and an (LF LR) (RF RR) signal (D signal).
  • the A signal is positioned as a main channel signal corresponding to the main signal (L R) of the present FM multiplex broadcasting system.
  • the 8" signal after being converted into a carrier suppressed AM signal wherein the frequency of the carrier is 38 KHZ or a doubled l9 KHZ pilot signal, is positioned as a first subchannel signal corresponding to the subsignal (L R) sin an of the present FM multiplex broadcasting systern.
  • the C signal and the D signal are converted in the same manner, that is, the C signal is positioned as a main channel signal (30 Hz 9 KHZ) corresponding to the A signal, and the D signal is positioned as a subchannel signal (10 KHZ 28 KHZ) corresponding to the B signal after being converted into a carrier suppressed AM signal wherein the frequency of the carrier is 19 KHZ which is the same as that of the pilot signal.
  • the C signal and the D signal which are positioned in a frequencyspectrum are positioned as a second sub-channel (57.5 KHZ 113.5 KHZ) higher than the first sub-channel (23 KHz 53 KHZ), after being frequency modulated into 85.5 KHZ 10 KHz. As is well known only one sideband of the 85.5Khz carrier need be transmitted.
  • the A, B, C" and D signals are converted and positioned as shown in the lower part of FIG. 1, further modulated into a frequency modulated signal by the frequency being used in a present FM stereo broadcasting system at present, and then transmitted.
  • a receiving antenna 21, an FM tuner 22 and a stereo decoder 23 are shown in a dotted line 24 and are the same as those in FM stereo receivers presently in use by the public. Therefore, the (LF LR) signal and the (RF RR) signal are led out from the output terminals of the stereo decoder 23.
  • One part of the output power of the FM tuner 22 is fed into an FM demodulator 25 for the second subchannel and is further frequency demodulated to produce an output signal containing the C signal and the D signal.
  • the output signal of the FM demodulator 2-5 is fed into a stereo decoder 26 for the second subchannel to be converted into the (LF LR) signal and the (RF RR) signal by the pilot signal which is supplied from the stereo decoder 23 and then the two converted signals are led out from output terminals of the decoder 26.
  • the (LF LR) signal and the (LF LR) signal are fed into a matrix circuit 27 and are added and subtracted to produce the LF signal and the LR signal on the two output terminals of the matrix circuit 27.
  • the (RF RR) signal and the (RF RR) signal are fed into a matrix circuit 28 and are added and subtracted to produce the RF signal and the RR signal on the two output terminals of the matrix circuit 28.
  • the received signal may be discriminated whether it is a monaural signal or a stereophonic signal by using the pilot signal being led out from the FM tuner 22, as in a prior art receiver. Furthermore, the received signal may be discriminated whether it is a two channel stereophonic signal or a four channel stereophonic signal by using the l9 KHz pilot signal being led out from the FM demodulator 25. Therefore, an automatic switching operation may be easily obtained so as to compose a reproduction circuit corresponding to either a monaural, two channel stereophonic or four channel stereophonic signal.
  • the present invention has many improvements, as described hereinabove.
  • compatibility can be obtained, that is, the invention gives satisfactory monophonic or two channel stereophonic reception on receivers presently in use by the public. in other words, if a monaural receiver receives the four channel stereophonic signal of the present invention, the mixed signal (LF LR RF RR) can be reproduced; and, if a two channel stereophonic receiver receives the four channel signal, the left signal (LF LR) and the right signal (RF RR) are reproduced.
  • the receiver of the invention receives a monaural signal
  • the monaural signal is reproduced by the front left and right and the rear left and right speakers
  • the receiver of the invention receives a twochannel stereophonic signal
  • the left signal of the stereophonic signal is reproduced by the front and rear speakers of the left side
  • the right signal is reproduced by the front and rear speakers of the right side.
  • the four signals that is, the front and the rear signals of the left side and those of the right side are equal to each other in their qualities, and it is easy to get more than 30 db in channel separation between each channel.
  • the system of the invention is capable of transmission on a present signal radie-frequency channel with no interference between neighboring radio-frequency channels.
  • a four channel stereophonic composite signal broadcasting system comprising a transmitter and at least one receiver, said transmitter comprising:
  • LF left front
  • RF right front
  • LR left rear
  • RR right rear
  • g. means for suppressed carrier amplitude modulating the D signal on a carrier of I9Khz producing a bandwidth of IOKhz-ZSKhz,
  • h. means for combining the C signal and the modulated D signal to produce a first composite signal in which the C signal occupies a bandwidth of 30hz-9Khz and the modulated D signal occupies a bandwidth of 10Khz-28Khz,
  • j. means for-frequency modulating said first composite signal on a carrier of 85.5Khz i lOKhz producing a bandwidth of 57.5Khz-1 13.5Khz,
  • m. means for broadcasting said frequency modulated second composite signal.
  • a first stereo decoder for obtaining an (LF LR) signal and an (RF RR) signal by using the output signal of said first FM demodulator circuit and a pilot signal, 1
  • a second stereo decoder for obtaining an (LF LR) signal and an (RF RR) signal by using the output signal of the second FM demodulator circuit and the pilot signal
  • matrix circuit means for combining said (LF LR), (RF RR), (LF LR) and (RF RR) signals to obtain LF, LR, RF and RR signals.
  • a four channel st'ereophonic composite signal broadcasting system including a transmitter comprisa. sources of left front (LF), right front (RF), left rear (LR) and right rear (RR) stereophonically related audio frequency signals,
  • signals including an (LF LR) signal and an (RF RR) signal
  • g. means for suppressed carrier amplitude modulating the D signal on a carrier of 19Khz producing a bandwidth of lOKhz28Khz,
  • h. means for combining the C signal and the modulated D signal to produce a first composite signal in which the C signal occupies a bandwidth of 30hz-9Khz and the modulated D signal occupies a bandwidth of lOKhz-28Khz,
  • j. means for frequency modulating said first compos' ite signal on a carrier of 85.5KhzilOKhz producing a bandwidth of 57.5Khzl 13.5Khz,
  • k means for combining said A signal, said pilot signal, said modulated B signal, and said frequency modulated first composite signal to produce a second composite signal in which said A signal occupies the bandwidth 30hz-15Khz, said modulated B signal occupies the bandwidth 23Khz-53Khz, and said modulated first composite signal occupies the bandwidth 57.5Khz-l 13.5Khz,
  • a first stereo decoder for obtaining an (LF LR) signal and an (RF RR) signal by using the output signal of said first FM demodulator circuit and the pilot signal
  • a second stereo decoder for obtaining an (LF LR) signal and an (RF RR) signal by using the output signal of the second FM demodulator circuit and the pilot signal
  • matrix circuit means for combining said (LF LR), (RF+ RR), (LF LR) and (RF RR) signals to obtain LF, LR, RF and RR signals.
  • a method of broadcasting a four channel stereophonic composite signal comprising the steps of a. generating left front (LF), right front (RF), left rear (LR) and right rear (RR) stereophonically related audio frequency signals,

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  • Engineering & Computer Science (AREA)
  • Multimedia (AREA)
  • Signal Processing (AREA)
  • Stereo-Broadcasting Methods (AREA)
  • Stereophonic System (AREA)
US00196932A 1970-11-09 1971-11-09 Four channel stereophonic broadcasting system Expired - Lifetime US3754099A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP45098513A JPS5033724B1 (enrdf_load_stackoverflow) 1970-11-09 1970-11-09

Publications (1)

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US3754099A true US3754099A (en) 1973-08-21

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US00196932A Expired - Lifetime US3754099A (en) 1970-11-09 1971-11-09 Four channel stereophonic broadcasting system

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US (1) US3754099A (enrdf_load_stackoverflow)
JP (1) JPS5033724B1 (enrdf_load_stackoverflow)
DE (1) DE2155336A1 (enrdf_load_stackoverflow)

Cited By (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3902018A (en) * 1973-12-03 1975-08-26 Zenith Radio Corp Multiple channel fm stereo system employing am vestigial sideband subcarrier modulation
US3904828A (en) * 1972-04-25 1975-09-09 Siemens Ag Compatible system for transmitting and receiving quadraphonic signals
US3906156A (en) * 1971-10-06 1975-09-16 Duane H Cooper Signal matrixing for directional reproduction of sound
US3944747A (en) * 1972-08-24 1976-03-16 Zenith Radio Corporation Multiple channel FM stereo system
US3965302A (en) * 1974-01-31 1976-06-22 Sansui Electric Co., Ltd. Stereo signal demodulator in a four-channel stereo broadcast receiver
US3970788A (en) * 1971-10-06 1976-07-20 Cooper Duane H Monaural and stereo compatible multidirectional sound matrixing
US4013841A (en) * 1971-12-23 1977-03-22 Matsushita Electric Industrial Co., Ltd. Four-channel stereo receiver
US4027107A (en) * 1973-09-28 1977-05-31 Zenith Radio Corporation Multiple channel FM stereo system
US4236039A (en) * 1976-07-19 1980-11-25 National Research Development Corporation Signal matrixing for directional reproduction of sound
US4301331A (en) * 1977-02-22 1981-11-17 Yurek John J Composite limiting sum and difference circuitry for extending the reception area of a frequency modulated stereo radio transmitter

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5051121U (enrdf_load_stackoverflow) * 1973-09-07 1975-05-17
JPH0366152U (enrdf_load_stackoverflow) * 1989-10-30 1991-06-27

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3679832A (en) * 1971-03-23 1972-07-25 Bell Telephone Labor Inc Three-channel fm stereo transmission
US3708623A (en) * 1970-04-29 1973-01-02 Quadracast Syst Inc Compatible four channel fm system

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3708623A (en) * 1970-04-29 1973-01-02 Quadracast Syst Inc Compatible four channel fm system
US3679832A (en) * 1971-03-23 1972-07-25 Bell Telephone Labor Inc Three-channel fm stereo transmission

Non-Patent Citations (2)

* Cited by examiner, † Cited by third party
Title
Quadrasonics On The Air, Feldman Audio Magazine, Jan. 1970. *
The Quart Broadcasting System, Geryon Audio Magazine, Sept. 1970. *

Cited By (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3906156A (en) * 1971-10-06 1975-09-16 Duane H Cooper Signal matrixing for directional reproduction of sound
US3970788A (en) * 1971-10-06 1976-07-20 Cooper Duane H Monaural and stereo compatible multidirectional sound matrixing
US4013841A (en) * 1971-12-23 1977-03-22 Matsushita Electric Industrial Co., Ltd. Four-channel stereo receiver
US3904828A (en) * 1972-04-25 1975-09-09 Siemens Ag Compatible system for transmitting and receiving quadraphonic signals
US3944747A (en) * 1972-08-24 1976-03-16 Zenith Radio Corporation Multiple channel FM stereo system
US4027107A (en) * 1973-09-28 1977-05-31 Zenith Radio Corporation Multiple channel FM stereo system
US3902018A (en) * 1973-12-03 1975-08-26 Zenith Radio Corp Multiple channel fm stereo system employing am vestigial sideband subcarrier modulation
US3965302A (en) * 1974-01-31 1976-06-22 Sansui Electric Co., Ltd. Stereo signal demodulator in a four-channel stereo broadcast receiver
US4236039A (en) * 1976-07-19 1980-11-25 National Research Development Corporation Signal matrixing for directional reproduction of sound
US4301331A (en) * 1977-02-22 1981-11-17 Yurek John J Composite limiting sum and difference circuitry for extending the reception area of a frequency modulated stereo radio transmitter

Also Published As

Publication number Publication date
JPS5033724B1 (enrdf_load_stackoverflow) 1975-11-01
DE2155336A1 (de) 1972-06-15

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