EP0420584B1 - PLL demodulating circuit in traffic information receiver - Google Patents

PLL demodulating circuit in traffic information receiver Download PDF

Info

Publication number
EP0420584B1
EP0420584B1 EP90310493A EP90310493A EP0420584B1 EP 0420584 B1 EP0420584 B1 EP 0420584B1 EP 90310493 A EP90310493 A EP 90310493A EP 90310493 A EP90310493 A EP 90310493A EP 0420584 B1 EP0420584 B1 EP 0420584B1
Authority
EP
European Patent Office
Prior art keywords
signal
traffic information
pll
pll circuit
circuit
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
EP90310493A
Other languages
German (de)
English (en)
French (fr)
Other versions
EP0420584A3 (en
EP0420584A2 (en
Inventor
Koichi C/O Pioneer Electronic Corporation Kasa
Toshihito C/O Pioneer Electronic Co. Ichikawa
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.)
Pioneer Corp
Original Assignee
Pioneer Electronic Corp
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
Family has litigation
First worldwide family litigation filed litigation Critical https://patents.darts-ip.com/?family=17218196&utm_source=google_patent&utm_medium=platform_link&utm_campaign=public_patent_search&patent=EP0420584(B1) "Global patent litigation dataset” by Darts-ip is licensed under a Creative Commons Attribution 4.0 International License.
Application filed by Pioneer Electronic Corp filed Critical Pioneer Electronic Corp
Publication of EP0420584A2 publication Critical patent/EP0420584A2/en
Publication of EP0420584A3 publication Critical patent/EP0420584A3/en
Application granted granted Critical
Publication of EP0420584B1 publication Critical patent/EP0420584B1/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

Links

Images

Classifications

    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04H—BROADCAST COMMUNICATION
    • H04H20/00—Arrangements for broadcast or for distribution combined with broadcast
    • H04H20/53—Arrangements specially adapted for specific applications, e.g. for traffic information or for mobile receivers
    • H04H20/55—Arrangements specially adapted for specific applications, e.g. for traffic information or for mobile receivers for traffic information
    • G—PHYSICS
    • G08—SIGNALLING
    • G08G—TRAFFIC CONTROL SYSTEMS
    • G08G1/00—Traffic control systems for road vehicles
    • G08G1/09—Arrangements for giving variable traffic instructions
    • G08G1/091—Traffic information broadcasting
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04H—BROADCAST COMMUNICATION
    • H04H20/00—Arrangements for broadcast or for distribution combined with broadcast
    • H04H20/28—Arrangements for simultaneous broadcast of plural pieces of information
    • H04H20/33—Arrangements for simultaneous broadcast of plural pieces of information by plural channels
    • H04H20/34—Arrangements for simultaneous broadcast of plural pieces of information by plural channels using an out-of-band subcarrier signal
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04H—BROADCAST COMMUNICATION
    • H04H40/00—Arrangements specially adapted for receiving broadcast information
    • H04H40/18—Arrangements characterised by circuits or components specially adapted for receiving
    • H04H40/27—Arrangements characterised by circuits or components specially adapted for receiving specially adapted for broadcast systems covered by groups H04H20/53 - H04H20/95

Definitions

  • the present invention relates to a PLL (phase locked loop) demodulating circuit in a traffic information receiver.
  • a traffic information bradcasting system (see DE-A-37 33 096 corresponding to JP-A-63-87 052) which supplies traffic information in such a manner as a time-sharing during a normal program of a braodcasting station for listeners to a car radio or the like.
  • a subcarrier of 57 kHz equal to a ternary harmonic of a stereophonic pilot signal of 19 kHz is used as a traffic information station identification (ID) signal (hereinafter, referred to as an SK signal) indicative of a broadcasting station of traffic information, the subcarrier frequency being out of the FM carrier band.
  • ID traffic information station identification
  • the subcarrier of 57 kHz amplitude modulated by a region ID signal (having one of the frequencies of from 23.75 Hz to 53.98 Hz which are equal to the values of the integer fractions of 57 kHz; this signal is hereinafter referred to as a BK signal) respectively designating a region the traffic information relates to and, further, by a message ID signal (a single tone of 125 Hz; this signal is referred to as a DK signal hereinafter) indicating that the traffic information is at present being broadcasted.
  • the amplitude modulated subcarrier modulates in frequency a main FM carrier which is transmitted as a traffic information broadcasting wave.
  • Fig. 3(a) shows a frequency spectrum of the above signals.
  • Fig. 3(b) shows a base band after the demodulation.
  • a receiver When a receiver receives the traffic information broadcasting wave it performs FM detection to produce a detection output, from which the SK signal is demodulated by a PLL circuit of 57 kHz and, further, the DK signal is demodulated by a PLL circuit of 125 Hz from the demodulated output.
  • a VCO voltage controlled oscillator
  • a VCO in the PLL circuit of 57 kHz has a locking range of about 1 % ( ⁇ 600 Hz) as shown in Fig. 4(a).
  • a VCO in the PLL circuit of 125 Hz has a locking range of about ⁇ 10 Hz as shown in Fig. 4(b).
  • the DK signal does not exist and, on the other hand, the SK and BK signals exist.
  • the difference between the lower BK signal frequency and the oscillating frequency of the VCO is equal to about 125 Hz of the DK signal as shown in Fig. 5(a). Therefore, there is a case where as shown in Fig. 5(b), the BK signal after the demodulation lies within a locking range of the PLL circuit for the DK signal and is locked into the particular PLL circuit, thereby causing erroneous detection of, the BK signal.
  • the present invention is made in view of the foregoing problem and it is an object of the invention to provide a PLL demodulating circuit in a traffic information receiver in which a demodulated BK signal is not locked into a PLL circuit for DK signal even if an influence by a multi-path phenomenon or the like is exerted.
  • a PLL demodulating circuit in a traffic information receiver for reception of an FM carrier wave carrying a subcarrier which is first ID signal indicative of a broadcasting station of traffic information which is amplitude modulated by a second ID signal indicating to which region the traffic information relates and by a third ID signal indicating that the traffic information is being broadcast, the amplitude modulated subcarrier being carried by a main FM carrier.
  • the receiver includes a first PLL circuit for demodulating the first ID signal from a detection output which is obtained by FM detection and a second PLL circuit for demodulating the third ID signal from a demodulated output of the first PLL circuit, and, assuming that the maximum frequency of the second ID signal is equal to BK and a frequency of the third ID signal is equal to DK, the locking ranges ⁇ f SK and ⁇ f DK of the first and second PLL circuits are determined so as to satisfy a condition of (DK - BK) > ( ⁇ f SK + ⁇ f DK ).
  • the total of the locking ranges of the first and second PLL circuits is not larger than the difference between the maximum frequency of the BK signal as a second ID signal and the frequency of the DK signal as a third ID signal.
  • Fig. 1 is a block diagram showing an outline of a fundamental construction of an FM multiplex broadcasting receiver which can receive a traffic information broadcasting.
  • the receiver can also receive an FM broadcasting wave in a radio data system which is so-called as RDS.
  • the radio data system is a system in which a broadcasting station braodcasts during a usual program a data signal having, information indicative of the kind of program content by means of a multiplex modulation and, a desired program content can be selected on the basis of the demodulated data on the reception side, that is, a radio listener.
  • a signal of 57 kHz is set to a subcarrier
  • the subcarrier of 57 kHz is amplitude modulated into the radio data signal by a data signal indicative of a program content which has been filtered and biphase encoded
  • the amplitude modulated subcarrier is carried by the main carrier which is broadcasted.
  • the RDS signal which was amplitude modulated by the data signal from the subcarrier (hereinafter, referred to as an SDS signal) which was amplitude modulated by the data signal from the subcarrier (hereinafter, referred to as an SDK signal) which was amplitude modulated by the DK signal of the traffic information broadcasting system
  • the RDS signal has a phase difference of about ⁇ /2 for the SDK signal.
  • the detection output of the FM detector 4 passes through a filter 6, so that the RDS signal or SDK signal as a subcarrier of 57 kHz is extracted and supplied to a PLL circuit 7.
  • the PLL circuit 7 the RDS signal or SDK signal which has been extracted from the FM detection output is demodulated.
  • the demodulated RDS signal is supplied to a digital (D) PLL circuit 8 and a decoder 9.
  • the SDK signal is supplied to a PLL circuit 10 to demodulate the DK signal.
  • the D-PLL circuit 8 produces clocks for data demodulation on the basis of the demodulated output of the PLL circuit 7.
  • the produced clocks are supplied to the decoder 9 and are also used as clocks when a process such as an error correction or the like is executed for the output data of the decoder 9.
  • the RDS signal as a demodulated output of the PLL circuit 7 is decoded synchronously with the clocks produced by the D-Pll circuit 8 and is output as data indicative of the kind of program content of the radio broadcasting.
  • a locking state detecting circuit 11 detects a locking state and an unlocking state of the D-PLL circuit 8 and controls the switching operation between the locking ranges of the PLL circuit 7 and D-PLL circuit 8 on the basis of the detection output.
  • a costas loop type PLL circuit is used as a PLL circuit 7.
  • Fig. 2 shows a construction of the costas loop type PLL circuit.
  • the RDS signal or SDK signal is individually multiplied with an output signal of a VCO (voltage controlled oscillator) 23 and a signal whose phase has been delayed by only ⁇ /2 by passing the VCO output through a phase shifting circuit 24.
  • the multiplied outputs are transmitted through LPFs (low pass filters) 25 and 26 and are multiplied by a mutiplier 27.
  • a harmonic component in an error signal as an output signal of the multiplier 27 is eliminated by a loop filter 28 and the resultant signal is used as a control voltage of the VCO 23.
  • the outputs of the multipliers 21 and 22 which have passed through the LPFs 25 and 26 are supplied to a selecting switch 29.
  • the selecting switch 29 is switched by, for instance, a detection signal issued from an SDK detecting circuit 30 for detecting a DC component of the output of the multiplier 21 which has passed through the LPF 25, thereby selectively passing therethrough either one of the outputs of the multipliers 21 and 22.
  • a selected output of the selecting switch 29 is derived as demodulated data.
  • the output of the multiplier 21 which has passed through the LPF 25 is extracted as an SDK signal and supplied to the PLL circuit 10 for DK (shown in Fig. 1).
  • the maximum change amount for the SK signal of the VCO 23 in the PLL circuit 7, that is, a locking range of the PLL circuit 7 is set to ⁇ f SK
  • the maximum change amount for the DK signal of the VCO (not shown) in the PLL circuit 10 is set to ⁇ f DK
  • the maximum frequency (53.98 Hz) of the BK signal is set to BK
  • the frequency (125Hz) of the DK signal is set to DK.
  • the locking ranges ⁇ f SK and ⁇ f DK of the PLL circuits 7 and 10 are determined so as to satify a condition of (DK - DB) > ( ⁇ f SK + ⁇ F DK ).
  • a digital PLL construction is formed by using a high accurate oscillator such as a crystal oscillator or the like as an oscillating source of a reference frequency of the PLL circuit 7 of 57 kHz and its locking range is set to about ⁇ 15 Hz. Since the PLL circuit 10 of 125 Hz generally has a locking range of about ⁇ 10 Hz as mentioned above, the difference between the maximum frequency of the DK signal and the maximum frequency of the BK signal is as follows (DK - BK) ⁇ 71 ( ⁇ f SK + ⁇ f DK ) ⁇ 25 even if it is influenced by the multi-path phenomenon. Accordingly, the BK signal after the demodulation does not fall into the locking range of the PLL circuit 10 for DK.
  • a high accurate oscillator such as a crystal oscillator or the like
  • the locking range of the PLL circuit of 57 kHz to demodulate the SDK signal from the FM detection output is set to ⁇ f SK
  • the locking range of the PLL circuit of 125 Hz to demodulate the DK signal from the PLL demodulated output is set to ⁇ f DK
  • the maximum frequency of the BK signal is set to BK
  • the frequency of the DK signal is set to DK
  • the locking ranges ⁇ f SK and ⁇ f DK of the PLL circuits are determined so as to satisfy the condition of (DK - BK) > ( ⁇ f SK + ⁇ f DK ). Therefore, the BK signal after the demodulation does not fall into the PLL circuit for DK of 125 Hz even if it is influenced by the multi-path noises or the like.

Landscapes

  • Engineering & Computer Science (AREA)
  • Signal Processing (AREA)
  • Circuits Of Receivers In General (AREA)
  • Synchronisation In Digital Transmission Systems (AREA)
EP90310493A 1989-09-27 1990-09-25 PLL demodulating circuit in traffic information receiver Expired - Lifetime EP0420584B1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
JP251135/89 1989-09-27
JP1251135A JPH0736532B2 (ja) 1989-09-27 1989-09-27 交通情報受信機におけるｐｌｌ復調回路

Publications (3)

Publication Number Publication Date
EP0420584A2 EP0420584A2 (en) 1991-04-03
EP0420584A3 EP0420584A3 (en) 1992-08-05
EP0420584B1 true EP0420584B1 (en) 1995-11-22

Family

ID=17218196

Family Applications (1)

Application Number Title Priority Date Filing Date
EP90310493A Expired - Lifetime EP0420584B1 (en) 1989-09-27 1990-09-25 PLL demodulating circuit in traffic information receiver

Country Status (3)

Country Link
EP (1) EP0420584B1 (ja)
JP (1) JPH0736532B2 (ja)
DE (1) DE69023729D1 (ja)

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP4788538B2 (ja) * 2006-09-12 2011-10-05 ソニー株式会社 ホログラム包装体

Family Cites Families (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE2408947C3 (de) * 1974-02-25 1979-02-22 Blaupunkt-Werke Gmbh, 3200 Hildesheim Schaltungsanordnung zur Frequenzerkennung auf dem Gebiet des Verkehrsfunkempfangs
DE2527857A1 (de) * 1975-06-23 1977-01-13 Blaupunkt Werke Gmbh Decoder fuer frequenzmodulierte steuersignale
JPS6387052A (ja) * 1986-09-30 1988-04-18 Pioneer Electronic Corp Ｆｍ多重放送受信機におけるデ−タ復調回路

Also Published As

Publication number Publication date
EP0420584A3 (en) 1992-08-05
JPH03113921A (ja) 1991-05-15
JPH0736532B2 (ja) 1995-04-19
EP0420584A2 (en) 1991-04-03
DE69023729D1 (de) 1996-01-04

Similar Documents

Publication Publication Date Title
US5507024A (en) FM data-system radio receiver
US5222252A (en) Stereo radio receiver multipath disturbance detection circuit
NO782914L (no) Mottaker for kompatible am stereo-signaler
AU645408B2 (en) AM-FM combined stereo receiver
US6661292B2 (en) Apparatus and method for demodulating a radio data system (RDS) signal
EP0420584B1 (en) PLL demodulating circuit in traffic information receiver
US4232189A (en) AM Stereo receivers
KR880000649B1 (ko) 다중톤(Tone) 파이롯트 신호 시스템
EP0471412B1 (en) Receivers for frequency modulated transmissions
US6704554B1 (en) Frequency modulation receiver in particular for an RDS application
JP2752388B2 (ja) Ｒｄｓ受信機におけるデータ復調回路
JPS6387052A (ja) Ｆｍ多重放送受信機におけるデ−タ復調回路
JPS6033014B2 (ja) ラジオ放送方式に用いる受信機
EP0949772B1 (en) Radio Data System (RDS) demodulator for receiving broadcast programmes carrying both Radio Data signals and ARI signals, comprising a digital filter means for obtaining a high attenuation of ARI signals
US4358638A (en) Apparatus for receiving an AM stereophonic signal
EP0293828B1 (en) Circuit device for demodulating DSB modulated signals and method therefor
JP4049444B2 (ja) 多重放送用受信装置
KR100219997B1 (ko) Fm 다중 방송 수신 회로 및 이를 사용한 수신기
AU645669B2 (en) AM-FM combined stereo receiver
KR820001531B1 (ko) 무선방송 시스템용 수신기
EP0972350A1 (en) Multiplex broadcast receiving method and receiver
KR830000672B1 (ko) Am 스테레오 수신기
JP3827381B2 (ja) Ｐｌｌ周波数シンセサイザ
CA1057357A (en) Compatible am stereophonic receivers
JPH0771050B2 (ja) 副搬送波同期回路

Legal Events

Date Code Title Description
PUAI Public reference made under article 153(3) epc to a published international application that has entered the european phase

Free format text: ORIGINAL CODE: 0009012

AK Designated contracting states

Kind code of ref document: A2

Designated state(s): DE FR GB

PUAL Search report despatched

Free format text: ORIGINAL CODE: 0009013

AK Designated contracting states

Kind code of ref document: A3

Designated state(s): DE FR GB

17P Request for examination filed

Effective date: 19921015

17Q First examination report despatched

Effective date: 19950331

GRAA (expected) grant

Free format text: ORIGINAL CODE: 0009210

AK Designated contracting states

Kind code of ref document: B1

Designated state(s): DE FR GB

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: FR

Effective date: 19951122

REF Corresponds to:

Ref document number: 69023729

Country of ref document: DE

Date of ref document: 19960104

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: DE

Effective date: 19960223

EN Fr: translation not filed
PLBI Opposition filed

Free format text: ORIGINAL CODE: 0009260

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: GB

Effective date: 19960925

PLBF Reply of patent proprietor to notice(s) of opposition

Free format text: ORIGINAL CODE: EPIDOS OBSO

26 Opposition filed

Opponent name: ROBERT BOSCH GMBH

Effective date: 19960819

PLBF Reply of patent proprietor to notice(s) of opposition

Free format text: ORIGINAL CODE: EPIDOS OBSO

GBPC Gb: european patent ceased through non-payment of renewal fee

Effective date: 19960925

PLBL Opposition procedure terminated

Free format text: ORIGINAL CODE: EPIDOS OPPC

PLBM Termination of opposition procedure: date of legal effect published

Free format text: ORIGINAL CODE: 0009276

STAA Information on the status of an ep patent application or granted ep patent

Free format text: STATUS: OPPOSITION PROCEDURE CLOSED

27C Opposition proceedings terminated

Effective date: 19971109