EP0944194A2 - Récepteur pour la réception de programmes de radiodiffusion numérique - Google Patents

Récepteur pour la réception de programmes de radiodiffusion numérique Download PDF

Info

Publication number
EP0944194A2
EP0944194A2 EP99105273A EP99105273A EP0944194A2 EP 0944194 A2 EP0944194 A2 EP 0944194A2 EP 99105273 A EP99105273 A EP 99105273A EP 99105273 A EP99105273 A EP 99105273A EP 0944194 A2 EP0944194 A2 EP 0944194A2
Authority
EP
European Patent Office
Prior art keywords
frequency
transmission mode
null
ensemble
signal
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.)
Withdrawn
Application number
EP99105273A
Other languages
German (de)
English (en)
Other versions
EP0944194A3 (fr
Inventor
Hiroshi Katsumoto
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.)
JVCKenwood Corp
Original Assignee
Kenwood KK
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 Kenwood KK filed Critical Kenwood KK
Publication of EP0944194A2 publication Critical patent/EP0944194A2/fr
Publication of EP0944194A3 publication Critical patent/EP0944194A3/fr
Withdrawn legal-status Critical Current

Links

Images

Classifications

    • 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
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04H—BROADCAST COMMUNICATION
    • H04H2201/00—Aspects of broadcast communication
    • H04H2201/10—Aspects of broadcast communication characterised by the type of broadcast system
    • H04H2201/20—Aspects of broadcast communication characterised by the type of broadcast system digital audio broadcasting [DAB]

Definitions

  • the present invention relates to a digital broadcast receiver, and more particularly to a digital broadcast receiver with a seek function of the type that when a seek is instructed, a plurality of digital broadcast frequencies are sequentially tuned in, and when a receivable digital broadcast station is found, the seek operation is terminated.
  • DAB digital audio broadcasting
  • OFDM orthogonal frequency division multiplex
  • Each transmission symbol is constituted of a guard interval and an effective symbol to thereby allow reception highly resistant to ghosts.
  • Each carrier of DAB is DQPSK modulated.
  • the DAB uses three bands: band II (87 to 108 MHz band), band III (175 to 250 MHz band), and L band (1.452 to 1.492 GHz band).
  • the band II and III utilize a transmission mode 1 having a transmission frame period of 96 ms and a carrier interval of 1 kHz.
  • the transmission mode 1 is highly resistant to multi-path and suitable for a single frequency network (SFN), and is limited to only for use with the bands II and III.
  • the L band utilizes transmission modes 2, 3, and 4.
  • the transmission mode 2 has a frame period of 24 ms and a carrier interval of 4 kHz and is suitable for mobil reception.
  • the transmission mode 3 has a frame period of 24 ms and a carrier interval of 8 kHz and is suitable for satellite broadcast or the like.
  • the transmission mode 4 has a frame period of 48 ms and a carrier interval of 2 kHz.
  • a transmission frame signal in the transmission mode 1 of DAB is shown in the upper portion of Fig. 3.
  • a sync signal constituted of a NULL symbol of 1.297 ms and a phase reference symbol (PRS: Phase Reference Symbol) in the initial field, and seventy five OFDM symbols each of 1.246 ms in the following fields.
  • Symbols other than the NULL symbol are transmission symbols.
  • a start period of 0.246 ms of each transmission symbol constitutes a guard interval, and the remaining period of 1 ms constitutes an effective symbol.
  • each symbol period shown in Fig. 3 is shortened by 1/4.
  • each symbol period shown in Fig. 3 is shortened by 1/8 and the number of OFDM symbols is increased.
  • each symbol period shown in Fig. 3 is shortened by 1/2.
  • Fig. 4 is a block diagram of a DAB receiver with a seek function.
  • a DAB broadcast signal (called ensemble) of, for example, in the band II, band III, or L band caught with an antenna 1 is sent to a front end 2, and the reception signal of the band II or III is input to an a terminal of an RF switch 3.
  • the reception signal of the L band is subject to a band limitation by a BPF 4, and is passed through an AGC amplifier 5 to be input to a mixer 6 whereat it is mixed with a local oscillation signal L 0 input from a PLL circuit 7 to be frequency-converted into a band of the band III.
  • the signal L 2 output from the PLL circuit 7 has a frequency of f 1 ⁇ (n 0 /m 0 ), where f 1 is a frequency of a reference oscillation signal input from a reference oscillator 13 to be described later, and m 0 and n 0 take fixed values.
  • An output of the mixer 6 is applied to a b terminal of the switch 3.
  • An envelope of an output of the mixer 6 is detected by an envelope detector 9 and output as an AGC voltage to the AGC amplifier 5.
  • the AGC amplifier 5 lowers or increases its gain in accordance with the AGC voltage so that an output of the mixer 6 has generally a constant level irrespective of the antenna input level.
  • An output of the RF switch 3 is RF-amplifier by an RF amplifier 10 capable of changing its gain with the AGC voltage and mixed at a mixer with a first local oscillation frequency L 1 supplied from a PLL circuit 12 to be converted into a first intermediate frequency signal having a center frequency of f IF1 .
  • the output L 1 of the PLL circuit has a frequency of f 1 ⁇ (n 1 /m 1 ), where f 1 is the frequency of a reference oscillation signal supplied from a reference oscillator 13, m 1 takes a fixed value, and n 1 takes a value which is changed by a system controller made of a microcomputer to be described later, n 1 being used for changing the tuned at a step of, for example, 16 kHz.
  • the reference oscillator 13 is a VCXO which changes its oscillation frequency in accordance with an automatic frequency adjusting control voltage.
  • the first intermediate frequency signal is supplied to a SAW filter (elastic surface wave filter) 14 to limit a pass-band to 1.536 MHz.
  • An output of the SAW filter 14 is supplied via an AGC amplifier 15 to a mixer 16 whereat it is mixed with a second local oscillation signal L 2 input from a PLL circuit 17 to be converted into a second intermediate frequency signal having a center frequency of f IF2 ( ⁇ f IF1 ).
  • the signal L 2 output from the PLL circuit 17 has a frequency of f 1 ⁇ (n 2 /m 2 ), where f 1 is a frequency of a reference oscillation signal input from the reference oscillator 13, and both m 2 and n 2 take fixed values.
  • the second intermediate frequency signal is supplied to an anti-aliasing filter 18 to limit a pass-band to 1.536 MHz.
  • An envelope of the second intermediate frequency signal output from the anti-aliasing filter 18 is detected by an envelope detector 19 and output as the AGC voltage to the RF amplifier 10 and AGC circuit 15 (refer to a in Fig. 3).
  • the RF amplifier 10 and AGC circuit 15 lower or increase their gains in accordance with the AGC voltage so that the second intermediate frequency signal having generally a constant level independent from the antenna input level can be obtained.
  • An output of the envelope detector 19 is input to a NULL detector 20 to detect a NULL symbol.
  • the NULL detector 20 shapes the waveform of the NULL symbol (refer to b in Fig. 3), and measures a low level time Td which corresponds to the NULL symbol period.
  • the timing sync circuit 21 generates various timing signals during an ordinary operation, by receiving carrier-components in the phase reference symbol PRS (effective symbol period) input from an FFT circuit to be described later, calculating a carrier-power, detecting a frame sync from a cepstrum obtained through IFFT of the carrier-power, and outputting this sync detection signal to an unrepresented timing signal generator. However, immediately after the start of ensemble reception, the timing sync circuit 21 detects the frame sync by using the NULL symbol detection signal ND input from the NULL detector 20, and outputs a sync detection signal.
  • the timing sync circuit 21 detects the frame sync by using the NULL symbol detection signal ND input from the NULL detector 20, and outputs a sync detection signal.
  • An output of the anti-aliasing filter 18 is A/D converted by an A/D converter 30.
  • An I/Q demodulator 31 demodulates I/Q components to recover the transmission frame signal shown in Fig. 3.
  • FFT Fast Fourier Transform
  • the FFT circuit 32 outputs the carrier-dependent components during the effective symbol period of PRS to a frequency error detector 33 in response to predetermined timing signals.
  • the frequency error detector 33 comprises a digital signal processor having a decoding software and decodes the carrier-dependent components of PRS through inter-carrier differential demodulation (for PRS, a predetermined fixed code was subject to the inter-carrier differential modulation on the transmission side), and thereafter calculates a correlation function between the decoded carrier-components and a predetermined reference code (e.g., conjugate of CAZAC code).
  • the correlation function is shown in the graph of Fig. 7). A frequency error of the tuned frequency from the DAB broadcast signal is calculated from this correlation function.
  • the frequency error detector 33 While AFC is enabled by the system controller, the frequency error detector 33 outputs frequency error data to an integrator 34 (while AFC is disabled, data indicating that the frequency error is zero is output). Data integrated by the integrator 34 is D/A converted by a D/A converter and output to the reference oscillator 13 as the automatic frequency adjusting control voltage. In accordance with this control voltage, the reference oscillator 13 changes its oscillation frequency to thereby change the reference oscillation signal frequency f 1 and cancel the frequency error.
  • the channel decoder 36 performs frequency deinterleaving, DQPSK symbol demapping, and FIC/MSC separation, and outputs packet data called an FIG (Fast Information Group) to the system controller, the FIG including twelve FIB's (Fast Information Blocks) obtained through error detection/correction (Viterbi decoding) and descrambling of three effective FIC symbols each divided into four.
  • MSC effective symbols are classified into eighteen symbols to reconfigure four CIF's (Common Interleaved Frames).
  • Each CIF contains a plurality of sub-channels each corresponding to one program.
  • the system controller 37 When a user selects a desired program by using a program select key of an operation panel 40, the system controller 37 performs a predetermined program selection control, and outputs information of designating a sub-channel corresponding to the desired program, by referring to FIC information.
  • the channel decoder 36 derives the sub-channel designated by the system controller 37 from four CIF's, and thereafter performs time deinterleaving, error detection/correction (Viterbi decoding), error count, and descrambling to output the demodulated DAB audio frame data to a MPEG decoder 38.
  • the MPEG decoder 38 decodes the DAB audio frame data and outputs audio data of two channels. This audio data is D/A converted by a D/A converter 39 and output as an analog audio signal.
  • the operation panel 40 is also provided with a seek key.
  • a memory 41 stores therein broadcast frequency data of a plurality of ensembles.
  • the system controller 37 Upon reception of a seek command, the system controller 37 supplies an AFC disable command to the frequency error detector 33 to make the latter output data indicating that the frequency error is zero and to fix the oscillation frequency of the reference oscillator 13 (Step S1 in Fig. 5).
  • Broadcast frequency data of the first ensemble is read from the memory 41, and if the reception signal is the band II or III, the RF switch 3 is turned to the terminal a , whereas if it is the L band, the RF switch 3 is turned to the b terminal.
  • the n 1 corresponding to the first ensemble frequency is set to the PLL circuit 12 to tune in to the first ensemble (Step S2).
  • the NULL detector 20 shapes the waveform of the output of the envelope detector 19, and outputs the NULL symbol detection signal at the rise timing of the envelope signal.
  • the system controller 32 Upon reception of the NULL symbol detection signal, the system controller 32 judges as YES at Step S3. Since there is a DAB broadcast signal at the present reception frequency, the system controller 37 supplies an AFC enable signal to the frequency error detector 33 to thereafter terminate the seek control process (Step S4).
  • An output of the front end 2 is I/Q demodulated by the I/Q demodulator 31, and is subject to FFT at the FFT circuit 32.
  • the carrier-components of PRS are decoded through inter-carrier differential demodulation by the frequency error detector 33, and thereafter a correlation function between the decoded carrier-components and a predetermined reference code is calculated.
  • An example of this correlation function is shown in the graph of Fig. 7 whose abscissa represents a frequency and ordinate represents a correlation value. In accordance with this correlation function, a frequency error of the tuned frequency from the DAB broadcast signal frequency can be calculated.
  • the corresponding correlation function becomes as shown in the graph of Fig. 7.
  • the AFC enable command is supplied to the frequency error detector 33, it outputs frequency error data representative of the frequency error calculated from the correlation function. This frequency error data is integrated by the integrator 34, D/A converted by the D/A converter 35, and supplied to the reference oscillator 13.
  • the reference oscillator 13 changes its oscillation frequency in accordance with the supplied control voltage, and changes the first and second local oscillation signals L 1 and L 2 so as to cancel the frequency error. Therefore, the spectrum distribution of the received ensemble relative to the first intermediate frequency signal shifts to the lower frequency (refer to an arrow C in Fig. 6), and ultimately enters the pass-band of the SAW filter 7 as indicated at A' in Fig. 8. It is therefore possible for the channel decoder 36 to correctly recover the information of FIC and MSC. As a user selects a desired program by using the operation panel 40, the system controller 37 instructs the channel decoder 36 to supply the DAB audio frame data of the desired program to the MPEG decoder 38. In this manner, the desired program can be listened.
  • Step S3 If NO at Step S3, there is no ensemble capable of being received at the presently tuned frequency, and the system controller 37 checks by referring to the memory 41 whether there is broadcast frequency data of the next ensemble (Step S5). If not, the seek control process is terminated, whereas if present, a corresponding n 1 is set to the PLL circuit 12, and after the new ensemble is tuned in, the above processes are repeated (Step S6).
  • the RF switch 3 is turned to the contact a . Isolation between the terminals b and c is about 50 dB. This isolation of the RF switch 3 is not sufficient because high AGC is incorporated in order to receive an antenna input of a minimum of - 90 dBm according to the DAB specification.
  • the reception signal frequency-converted by the mixer 6 is attenuated by 50 dB by the RF switch 3 (refer to B in Fig. 9B), it is amplified by the RF amplifier 10 and AGC amplifier 15 (refer to C in Fig. 9C).
  • a digital broadcast receiver comprises reception means for tuning a selected broadcast frequency to receive a digital broadcast signal of an OFDM modulated wave in the tuned broadcast frequency; deriving means for deriving carrier-components from an output of the reception means; program information demodulating means for demodulating information part (FIC, MSC) of the derived carrier-components to recover a program desired by a user; frequency error detecting means for detecting a tuning frequency error by referring to a correlation function calculated from control part (PRS) of the derived carrier-component and a reference code; frequency adjusting means for adjusting the tuning frequency in the reception means to eliminate the detected tuning frequency error; NULL detecting means for detecting a NULL symbol in the output of the reception means; and control means for in response to a seek instruction controlling the reception means to sequentially tune each of broadcast frequencies of the digital broadcast signal and stop the seek operation when the NULL detecting means detects the NULL symbol at one of the sequentially tuned broadcast frequencies and then controlling the frequency adjusting means to conduct the tuning frequency adjustment at
  • said NULL symbol detecting means generates a transmission mode signal which represents the NULL symbol period and send the transmission mode signal to said control means.
  • said control means further judges whether or not the tuning frequency error adjusted by the frequency adjusting means when the seek operation is stopped is less than a predetermined value after a preselected time period has elapsed, and resumes the seek operation if the tuning frequency error is not less so that the reception means tunes the next broadcast frequency.
  • said control means turns off the tuning frequency adjustment operation by the frequency adjusting means during the seek operation.
  • Fig. 1 is a block diagram of a DAB receiver with a seek function according to the embodiment of the invention.
  • like elements to those shown in Fig. 4 are represented by using identical reference numerals.
  • a system controller 37A constituted of a microcomputer performs a predetermined seek control process upon reception of a seek instruction entered by depressing the seek key of an operation panel 40, and performs a predetermined program selection control upon reception of a program selection instruction entered by the program select key.
  • the conditions of terminating the seek control process are that a NULL symbol is detected, and that the transmission mode of an ensemble to be sought is coincident with the transmission mode detected by a NULL detector 20.
  • Fig. 2 is a flow chart illustrating the seek control process to be executed by the system controller 37A.
  • a memory 41 stores in advance broadcast frequency data of ten ensembles of the bands II and III and the L band, in memory channels CH1 to CH10.
  • the system controller 37A Upon reception of a seek command entered from a user by depressing the seek key of the operation panel 40, the system controller 37A supplies an AFC disable command to a frequency error detector 33A to make the latter output data indicating that the frequency error is zero and to fix the oscillation frequency of a reference oscillator 13 (Step S11 in Fig. 2).
  • Broadcast frequency data of the first ensemble is read from the memory 41 in the memory channel CH1, and if the reception signal corresponds to the band II or III, an RF switch 3 is turned to a terminal, whereas if it corresponds to the L band, the switch 3 is turned to a b terminal.
  • a value n 1 corresponding to the broadcast frequency data of the first ensemble is set to a PLL circuit 12 to tune in to the first ensemble (Step S12).
  • Step S13 it is checked whether the NULL symbol detection signal ND is supplied from a NULL detector 20 (Step S13). If NO, there is no possibility that the ensemble is received at the present reception frequency.
  • broadcast frequency data of the next ensemble stored in the memory 41 in the memory channel CH2 is read, and if the reception signal corresponds to the band II or III, the RF switch 3 is turned to a terminal, whereas if it corresponds to the L band, the switch 3 is turned to a b terminal.
  • the value n 1 corresponding to the broadcast frequency data of the second ensemble is set to the PLL circuit 12 to tune in to the second ensemble (Steps S14 and S15).
  • the front end 2 When the ensemble or DAB broadcast signal is captured at the present reception frequency, the front end 2 outputs the second intermediate frequency signal, and an output of the NULL symbol from an envelope detector 19 lowers.
  • the NULL detector 20 shapes the waveform of the output of the envelope detector 19, and measures a low level time Td. If this low level time is coincident with a NULL symbol length of any transmission mode defined by DAB, the NULL detector 13 outputs a NULL symbol detection signal ND synchronously with the rise timing of the envelope signal (refer to Fig. 3).
  • a timing sync circuit 21 detects a frame sync, and outputs a sync detection signal to an unrepresented timing signal generator which generates various timing signals.
  • the system controller 37A Upon reception of the NULL symbol detection signal ND, the system controller 37A judges as YES at Step S13. However, it is uncertain that the received ensemble is the band II or III, or the L band as viewed from the output of the front end 2.
  • the system controller 37A fetches the transmission mode detection signal TM from the NULL detector 20. If the ensemble to be sought is the band II or III, the transmission mode 1 is used (if a transmission distance of a radio wave is long and SFN is used, the transmission mode 1 is used in order to have a sufficient length of the guard interval). It is therefore checked whether the transmission mode designated by the transmission detection signal TM is the transmission mode 1 (Step S16). If not, it is judged that the NULL symbol was accidentally detected because an ensemble of the L band was frequency-converted to the band III, and the flow advances to Step S14.
  • the ensemble to be sought is the band II or III and the transmission mode designated by the transmission detection signal TM is the transmission mode 1, there is a high possibility that the presently received ensemble is an ensemble to be sought.
  • the AFC enable command is therefore supplied to the frequency error detector 33A, and a timer for counting up a predetermined time is made to start (Steps S17 and S18).
  • the permitted transmission modes are modes 2, 3, and 4. It is therefore judged at Step S16 whether the transmission mode designated by the transmission detection signal TM is coincident with one of the transmission modes 2, 3, and 4. If not coincident, it is judged that the NULL symbol was accidently detected because some ensemble of the band II or III leaked to the output side of the RF switch 3, and the flow advances to Step S14.
  • the ensemble to be sought is the L band and the transmission mode designated by the transmission detection signal TM is one of the transmission modes 2, 3, and 4, there is a high possibility that the presently received ensemble is an ensemble to be sought.
  • the AFC enable command is therefore supplied to the frequency error detector 33A, and the timer for counting up a predetermined time is made to start (Steps S17 and S18).
  • An output of the front end 2 is I/Q demodulated by an I/Q demodulator 31, and is subject to a FFT process by a FFT circuit 32.
  • the frequency error detector 33A received the AFC enable command decodes the carrier-dependent components through inter-carrier differential demodulation and calculates a correlation function between the carrier-dependent components and a predetermined reference code.
  • a frequency error is calculated, and the calculated frequency error data is supplied to an integrator 34.
  • the frequency error data is integrated by the integrator 34, D/A converted by a D/A converter 35, and output as an automatic frequency adjusting control voltage to the reference oscillator 13.
  • the reference oscillator 13 changes its oscillation frequency f 1 with this control voltage to change the frequencies of the first and second local oscillation signals L 1 and L 2 to cancel the frequency error.
  • the frequency error does not become small even if a time lapses after the AFC enable command and the ensemble cannot be received correctly. If the detection of the NULL symbol is originated not from an ensemble but from a dip formed during a mobile reception on the time axis of a TV broadcast signal or the like other than DAB broadcast signals, because of fading phenomenon or the like and if the maximum correlation value accidentally becomes equal to or higher than the reference value S c , the frequency error does not become small even if a time lapses after the AFC enable command.
  • the system controller 37A checks whether the current frequency error data fetched from the frequency error detector 33A has converged into a predetermined value or lower (Steps S19 and S20). If NO, it is judged that the NULL symbol of the transmission mode 1 was detected because, for example, a dip formed during a mobile reception on the time axis of a TV broadcast signal because of fading phenomenon or the like was erroneously detected as the NULL symbol. Then, the system controller 37A supplies the AFC disable command to the frequency error detector 33A (step S21), and the flow advances to Step S14 whereat the next ensemble corresponding to the memory channel CH2 is tuned in to repeat the above processed.
  • a channel decoder 36 recovers information of FIC and MSC from the carrier-independent components of each symbol input from the FFT circuit 32.
  • the system controller 37A instructs the channel decoder 36 to output the DAB audio frame data of the desired program to a MPEG decoder 38. In this manner, the desired program can be listened.
  • the NULL symbol is detected at some reception frequency of an ensemble during the seek operation and if the transmission mode detected by the NULL detector 20 is coincident with the transmission mode 1 because if the ensemble to be sought is the band II or III, the transmission mode is the mode 1, then the AFC is enabled and the seek operation is terminated if the frequency error converges to the predetermined value or lower in the predetermined time. In this manner, the ensemble to be sought can be correctly received. If the ensemble to be sought is the L band, the mode is only the transmission modes 2, 3, and 4.
  • the AFC is enabled and the seek operation is terminated if the frequency error converges to the predetermined value or lower in the predetermined time. In this manner, the ensemble to be sought can be correctly received.
  • DAB broadcasting in Europe is used.
  • the invention is not limited only to the DAB broadcasting, but is also applicable to other broadcasting and communications such as digital ground wave TV broadcasting and digital satellite broadcasting.
  • the seek operation is terminated to correctly receive the ensemble to be sought.

Landscapes

  • Engineering & Computer Science (AREA)
  • Signal Processing (AREA)
  • Circuits Of Receivers In General (AREA)
  • Channel Selection Circuits, Automatic Tuning Circuits (AREA)
EP99105273A 1998-03-18 1999-03-15 Récepteur pour la réception de programmes de radiodiffusion numérique Withdrawn EP0944194A3 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
JP9082398 1998-03-18
JP09082398A JP3514624B2 (ja) 1998-03-18 1998-03-18 ディジタル放送受信機

Publications (2)

Publication Number Publication Date
EP0944194A2 true EP0944194A2 (fr) 1999-09-22
EP0944194A3 EP0944194A3 (fr) 2003-09-10

Family

ID=14009323

Family Applications (1)

Application Number Title Priority Date Filing Date
EP99105273A Withdrawn EP0944194A3 (fr) 1998-03-18 1999-03-15 Récepteur pour la réception de programmes de radiodiffusion numérique

Country Status (4)

Country Link
EP (1) EP0944194A3 (fr)
JP (1) JP3514624B2 (fr)
CA (1) CA2265259C (fr)
DE (1) DE944194T1 (fr)

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP1150469A2 (fr) * 2000-04-28 2001-10-31 Kabushiki Kaisha Kenwood Réaccordage dans un récepteur pour la radiodiffusion numérique
US7006577B2 (en) * 2000-08-16 2006-02-28 Samsung Electronics Co., Ltd. Apparatus and method for detecting transmission mode in digital audio receiver using null symbols
EP1841107A2 (fr) * 2006-03-30 2007-10-03 Beijing Nufront Software Tech. Co., Ltd Récepteur T-MMB compatible avec DAB
US20080049882A1 (en) * 2004-09-02 2008-02-28 Robert Bosch Gmbh Receiving Device for Receiving Time-Multiplexed Signals, Transmitting System, and Method for Time Synchronization of Time-Multiplexed Signals
US7933368B2 (en) 2007-06-04 2011-04-26 Ibiquity Digital Corporation Method and apparatus for implementing a digital signal quality metric
US7933367B2 (en) 2007-06-04 2011-04-26 Ibiquity Digital Corporation Method and apparatus for implementing seek and scan functions for an FM digital radio signal
EP2854314A1 (fr) * 2013-09-06 2015-04-01 Sven Mulka Procédé et dispositif pour l'insertion de messages d'alarme dans un ensemble DAB dans un tunnel

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE4403408C1 (de) * 1994-02-04 1995-02-23 Grundig Emv Verfahren zur Erkennung eines Übertragungs-Modes
EP0786889A1 (fr) * 1996-02-02 1997-07-30 Deutsche Thomson-Brandt Gmbh Procédé et appareil de réception de signaux à porteuses multiples

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE4403408C1 (de) * 1994-02-04 1995-02-23 Grundig Emv Verfahren zur Erkennung eines Übertragungs-Modes
EP0786889A1 (fr) * 1996-02-02 1997-07-30 Deutsche Thomson-Brandt Gmbh Procédé et appareil de réception de signaux à porteuses multiples

Non-Patent Citations (2)

* Cited by examiner, † Cited by third party
Title
A. JONGEPIER: "Eureka 147 DAB : Receiver and test system developments" 14 March 1994 (1994-03-14) , INTERNATIONAL SYMPOSIUM ON DIGITAL AUDIO BROADCASTING, XX, XX, VOL. II, PAGES 250-260 , TORONTO, CANADA XP002247002 * page 251, line 22 - line 24 * * page 255 * *, sentence 3 - sentence 6 * * page 255, line 13 * *
ROMANOWSKI A ET AL: "Concept of a multistandard receiver for digital broadcast and communication services" , 1997 INTERNATIONAL CONFERENCE ON CONSUMER ELECTRONICS, ROSEMONT, IL, USA, 11-13 JUNE 1997 , IEEE TRANSACTIONS ON CONSUMER ELECTRONICS, AUG. 1997, IEEE, USA, PAGE(S) 662 - 670 XP010250064 ISSN: 0098-3063 * the whole document * *

Cited By (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP1150469A2 (fr) * 2000-04-28 2001-10-31 Kabushiki Kaisha Kenwood Réaccordage dans un récepteur pour la radiodiffusion numérique
EP1150469A3 (fr) * 2000-04-28 2004-08-18 Kabushiki Kaisha Kenwood Réaccordage dans un récepteur pour la radiodiffusion numérique
US7006577B2 (en) * 2000-08-16 2006-02-28 Samsung Electronics Co., Ltd. Apparatus and method for detecting transmission mode in digital audio receiver using null symbols
US20080049882A1 (en) * 2004-09-02 2008-02-28 Robert Bosch Gmbh Receiving Device for Receiving Time-Multiplexed Signals, Transmitting System, and Method for Time Synchronization of Time-Multiplexed Signals
US8340238B2 (en) * 2004-09-02 2012-12-25 Robert Bosch Gmbh Receiving device for receiving time-multiplexed signals, transmitting system, and method for time synchronization of time-multiplexed signals
EP1841107A2 (fr) * 2006-03-30 2007-10-03 Beijing Nufront Software Tech. Co., Ltd Récepteur T-MMB compatible avec DAB
EP1841107A3 (fr) * 2006-03-30 2011-11-23 Beijing Nufront Mobile Multimedia Technology Co., Ltd. Récepteur T-MMB compatible avec DAB
US7933368B2 (en) 2007-06-04 2011-04-26 Ibiquity Digital Corporation Method and apparatus for implementing a digital signal quality metric
US7933367B2 (en) 2007-06-04 2011-04-26 Ibiquity Digital Corporation Method and apparatus for implementing seek and scan functions for an FM digital radio signal
EP2854314A1 (fr) * 2013-09-06 2015-04-01 Sven Mulka Procédé et dispositif pour l'insertion de messages d'alarme dans un ensemble DAB dans un tunnel
EP3627729A1 (fr) * 2013-09-06 2020-03-25 Sven Mulka Procédé et dispositif d'affichage des messages d'alarme dans un ensemble dab à l'intérieur d'un tunnel

Also Published As

Publication number Publication date
JP3514624B2 (ja) 2004-03-31
DE944194T1 (de) 2000-02-17
EP0944194A3 (fr) 2003-09-10
JPH11275045A (ja) 1999-10-08
CA2265259C (fr) 2006-06-06
CA2265259A1 (fr) 1999-09-18

Similar Documents

Publication Publication Date Title
JP3549361B2 (ja) ディジタル音声放送受信機
EP1848119A1 (fr) Récepteur à diversité
CA2265259C (fr) Recepteur de diffusion numerique
US8121566B2 (en) Broadcast receiver and broadcast channel seek method
KR100609504B1 (ko) 수신기
CA2265260C (fr) Recepteur de diffusion numerique
JP3457622B2 (ja) デジタル放送受信装置
EP0944193B1 (fr) Récepteur pour la réception de programmes de radiodiffusion numérique
JP2003069907A (ja) 地上デジタル放送受信装置
JP4173171B2 (ja) ラジオ受信機及び搬送波検出方法
JP3568186B2 (ja) ディジタル放送受信機
JP3363764B2 (ja) Ｏｆｄｍ放送受信機
JP3394186B2 (ja) ディジタル放送受信機
JP3514625B2 (ja) ディジタル放送受信機
JP3798604B2 (ja) 放送方式判別装置及び放送方式判別方法
JP3656797B2 (ja) デジタル放送受信機
JP2001211136A (ja) ディジタル放送受信機及びセグメント数検出装置
EP1150469A2 (fr) Réaccordage dans un récepteur pour la radiodiffusion numérique
JP2002374467A (ja) デジタル放送受信機
KR100252936B1 (ko) 위성방송수신기의엘엔비(lnb)의국부발진주파수설정방법
JP2002374468A (ja) デジタル放送受信機
JP2000124823A (ja) 放送受信装置
JPH10200499A (ja) デジタルオーディオ放送用受信機のネットワークフォロー装置
JPH06338814A (ja) 多重放送受信機

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): AT BE CH CY DE DK ES FI FR GB GR IE IT LI LU MC NL PT SE

AX Request for extension of the european patent

Free format text: AL;LT;LV;MK;RO;SI

EL Fr: translation of claims filed
DET De: translation of patent claims
PUAL Search report despatched

Free format text: ORIGINAL CODE: 0009013

RIC1 Information provided on ipc code assigned before grant

Ipc: 7H 04B 1/10 B

Ipc: 7H 04H 1/00 A

AK Designated contracting states

Kind code of ref document: A3

Designated state(s): AT BE CH CY DE DK ES FI FR GB GR IE IT LI LU MC NL PT SE

AX Request for extension of the european patent

Extension state: AL LT LV MK RO SI

17P Request for examination filed

Effective date: 20040309

AKX Designation fees paid

Designated state(s): DE FR GB

17Q First examination report despatched

Effective date: 20040510

RAP1 Party data changed (applicant data changed or rights of an application transferred)

Owner name: KABUSHIKI KAISHA KENWOOD

RAP1 Party data changed (applicant data changed or rights of an application transferred)

Owner name: JVC KENWOOD CORPORATION

GRAP Despatch of communication of intention to grant a patent

Free format text: ORIGINAL CODE: EPIDOSNIGR1

RIC1 Information provided on ipc code assigned before grant

Ipc: H04H 40/18 20080101AFI20160502BHEP

INTG Intention to grant announced

Effective date: 20160518

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

Free format text: STATUS: THE APPLICATION IS DEEMED TO BE WITHDRAWN

18D Application deemed to be withdrawn

Effective date: 20160929

REG Reference to a national code

Ref country code: HK

Ref legal event code: WD

Ref document number: 1023007

Country of ref document: HK