AU588479B2 - A capture circuit for restoring the carrier from a qam-signal - Google Patents

A capture circuit for restoring the carrier from a qam-signal

Info

Publication number
AU588479B2
AU588479B2 AU77633/87A AU7763387A AU588479B2 AU 588479 B2 AU588479 B2 AU 588479B2 AU 77633/87 A AU77633/87 A AU 77633/87A AU 7763387 A AU7763387 A AU 7763387A AU 588479 B2 AU588479 B2 AU 588479B2
Authority
AU
Australia
Prior art keywords
interruption
vco
event
circuit
carrier
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.)
Ceased
Application number
AU77633/87A
Other versions
AU7763387A (en
Inventor
Klaus Boshold
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.)
Siemens AG
Original Assignee
Siemens AG
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 Siemens AG filed Critical Siemens AG
Publication of AU7763387A publication Critical patent/AU7763387A/en
Application granted granted Critical
Publication of AU588479B2 publication Critical patent/AU588479B2/en
Anticipated expiration legal-status Critical
Ceased legal-status Critical Current

Links

Classifications

    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L27/00—Modulated-carrier systems
    • H04L27/32—Carrier systems characterised by combinations of two or more of the types covered by groups H04L27/02, H04L27/10, H04L27/18 or H04L27/26
    • H04L27/34—Amplitude- and phase-modulated carrier systems, e.g. quadrature-amplitude modulated carrier systems
    • H04L27/38—Demodulator circuits; Receiver circuits
    • H04L27/3818—Demodulator circuits; Receiver circuits using coherent demodulation, i.e. using one or more nominally phase synchronous carriers
    • H04L27/3836—Demodulator circuits; Receiver circuits using coherent demodulation, i.e. using one or more nominally phase synchronous carriers in which the carrier is recovered using the received modulated signal or the received IF signal, e.g. by detecting a pilot or by frequency multiplication

Landscapes

  • Engineering & Computer Science (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Signal Processing (AREA)
  • Digital Transmission Methods That Use Modulated Carrier Waves (AREA)
  • Reduction Or Emphasis Of Bandwidth Of Signals (AREA)
  • Television Systems (AREA)
  • Radio Relay Systems (AREA)
  • Apparatus For Radiation Diagnosis (AREA)
  • Measurement And Recording Of Electrical Phenomena And Electrical Characteristics Of The Living Body (AREA)

Abstract

The circuit is provided for the demodulation circuit of a digital radio system, consisting of a demodulator (D), a voltage-controlled oscillator (VCO) and a carrier signal control voltage generator (TR) with a level monitor (P) at its input and an error monitor (F) for the bit error rate at its output. It is designed to synchronise carrier recovery within the shortest possible time following signal interruption, e.g. due to fading. A memory circuit (SP) is disposed between the carrier signal control voltage generator (TR) and the voltage-controlled oscillator (VCO), which ensures that, when the signal returns, the VCO continues to oscillate at the frequency prevailing before the interruption. In the event of an expected interruption in signal transmission, indicated by a rise in the bit error rate above a defined threshold, the error monitor (F) initiates the disconnection of the memory circuit (SP) from the VCO input before the interruption occurs. A sweep generator (W) with a preceding delay circuit (V) connected between the error monitor (F) and the carrier signal control voltage generator (TR) ensures the locking function in any event e.g. in the event of frequency offset following a long interruption. <IMAGE>
AU77633/87A 1986-08-28 1987-08-27 A capture circuit for restoring the carrier from a qam-signal Ceased AU588479B2 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE3629184 1986-08-28
DE3629184 1986-08-28

Publications (2)

Publication Number Publication Date
AU7763387A AU7763387A (en) 1988-03-03
AU588479B2 true AU588479B2 (en) 1989-09-14

Family

ID=6308329

Family Applications (1)

Application Number Title Priority Date Filing Date
AU77633/87A Ceased AU588479B2 (en) 1986-08-28 1987-08-27 A capture circuit for restoring the carrier from a qam-signal

Country Status (4)

Country Link
EP (1) EP0257625B1 (en)
AT (1) ATE70930T1 (en)
AU (1) AU588479B2 (en)
DE (1) DE3775494D1 (en)

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE4041701C1 (en) * 1990-12-24 1992-06-25 Ant Nachrichtentechnik Gmbh, 7150 Backnang, De
DE19717642A1 (en) 1997-04-25 1998-11-05 Siemens Ag Data regeneration procedure

Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
AU569199B2 (en) * 1985-10-25 1988-01-21 Siemans A.G. Carrier recovery from a qam signal

Family Cites Families (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS58190135A (en) * 1982-04-30 1983-11-07 Nec Corp Phase synchronising circuit
JPS613553A (en) * 1984-06-15 1986-01-09 Fujitsu Ltd Carrier recovery circuit

Patent Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
AU569199B2 (en) * 1985-10-25 1988-01-21 Siemans A.G. Carrier recovery from a qam signal

Also Published As

Publication number Publication date
EP0257625A3 (en) 1989-03-01
AU7763387A (en) 1988-03-03
EP0257625A2 (en) 1988-03-02
DE3775494D1 (en) 1992-02-06
EP0257625B1 (en) 1991-12-27
ATE70930T1 (en) 1992-01-15

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