EP0686318A1 - Syntoniseur haute frequence a large bande - Google Patents

Syntoniseur haute frequence a large bande

Info

Publication number
EP0686318A1
EP0686318A1 EP95901580A EP95901580A EP0686318A1 EP 0686318 A1 EP0686318 A1 EP 0686318A1 EP 95901580 A EP95901580 A EP 95901580A EP 95901580 A EP95901580 A EP 95901580A EP 0686318 A1 EP0686318 A1 EP 0686318A1
Authority
EP
European Patent Office
Prior art keywords
frequency
bandpass filter
tuner
mixer stage
oscillator
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Withdrawn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
EP95901580A
Other languages
German (de)
English (en)
Inventor
Bartele Bouma
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.)
Koninklijke Philips NV
Original Assignee
Koninklijke Philips Electronics NV
Philips Electronics NV
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 Koninklijke Philips Electronics NV, Philips Electronics NV filed Critical Koninklijke Philips Electronics NV
Priority to EP95901580A priority Critical patent/EP0686318A1/fr
Publication of EP0686318A1 publication Critical patent/EP0686318A1/fr
Withdrawn legal-status Critical Current

Links

Classifications

    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04B—TRANSMISSION
    • H04B1/00—Details of transmission systems, not covered by a single one of groups H04B3/00 - H04B13/00; Details of transmission systems not characterised by the medium used for transmission
    • H04B1/06—Receivers
    • H04B1/16—Circuits
    • H04B1/26—Circuits for superheterodyne receivers
    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03J—TUNING RESONANT CIRCUITS; SELECTING RESONANT CIRCUITS
    • H03J3/00—Continuous tuning
    • H03J3/02—Details
    • H03J3/06—Arrangements for obtaining constant bandwidth or gain throughout tuning range or ranges
    • H03J3/08—Arrangements for obtaining constant bandwidth or gain throughout tuning range or ranges by varying a second parameter simultaneously with the tuning, e.g. coupling bandpass filter

Definitions

  • the invention relates to a high-frequency wideband tuner for converting signals in an radio-frequency (r.f.) band that ranges from a frequency f(l) to a frequency f(2) in an intermediate frequency signal having a fixed frequency f(if), comprising a tunable r.f. bandpass filter, an oscillator and a mixer stage which has a first input for the output signal of the bandpass filter and a second input for the signal produced by the oscillator.
  • the invention specifically relates to a tuner for signals transmitted by broadcasting satellites.
  • Such a tuner is described in the article "Television Broadcasting from Satellites” by D.B. Spencer in Wireless World, March 1974, pp. 39-44. This article particularly relates to the problems with respect to image frequencies which may occur in this type of tuners.
  • the frequency band used by the broadcasting satellites may currently range from 10.95 to 12.75 GHz and to date it is customary for this frequency band to be split up at the satellite antenna into a band from 10.95-11.7 GHz which is converted to an intermediate frequency band from 9.50-1700 MHz by a first low noise converter (LNC) whose oscillator has a 10 GHz frequency, and to a band from 11.7-12.75 GHz which is converted to an intermediate frequency band from 950-2000 MHz by a second low noise converter (LNC) whose oscillator has a 10.75 GHz frequency.
  • LNC low noise converter
  • the two intermediate frequency bands thus obtained are applied to a tuner having a tuning range from 950-2000 MHz which produces for its output signal the television signal transmitted by the satellite.
  • a tuner is to be used which can cover this range completely and which can convert the signal in this band to a second intermediate frequency signal having a frequency of, for example, 479.5 MHz (the second intermediate frequency determined to be used in Europe).
  • Such a tuner is unavailable for the moment and, with a conventional design for a tuner, cannot be realised either, because the oscillator of such a conventional tuner would have to have a frequency range from 1429.5-3229.5 MHz, which is even hard to realise with three varicaps, but would also have to contain a tunable bandpass filter for the range from 950-2750 MHz, which cannot (yet) be realised with the techniques currently available.
  • Another option is to provide a twofold tuner comprising two bandpass filters, two mixer stages and two oscillators, in which there are adjacent frequency ranges and they together cover the desired frequency band. Obviously, such a solution is extra costly due to the twofold configuration of a number of high-frequency circuits which are costly by themselves.
  • the invention comprises a tuner of said type,
  • the invention is based on the recognition that an oscillator having a limited frequency range (about 2xf(if)) can be used in combination with a pair of tunable bandpass filters which have each a limited frequency range, if the output signal of the first bandpass filter is converted to the desired intermediate frequency signal by the implementation of the double heterodyne principle and the output signal of the second bandpass filter is converted to the same intermediate frequency signal by the implementation of the single heterodyne principle.
  • Reference character 1 in the drawing Figure denotes a satellite dish antenna arranged for receiving television signals in a frequency band, for example, from 10.95 GHz to 12.75 GHz.
  • the signal received by antenna 1 is applied via an amplifier 2 to a first input of a mixer stage i.e. mixer 3, whose second input receives the output signal of an oscillator 4 which has, for example, a fixed frequency of 10 GHz.
  • the amplifier 2, mixer 3 and oscillator 4 together form a low noise converter LNC 5.
  • the output signal of the LNC 5 which then has a frequency range from 950-2750 MHz, is applied to a tuner according to the invention, which tuner as a whole is denoted by reference character 6.
  • the tuner 6 comprises a first tunable bandpass filter 7 and a second tunable bandpass filter 8.
  • the output signal of either filter 7 or 8 may be applied via switch 9 to a first input of a mixer 10 whose second input receives the output signal of the tunable oscillator 11.
  • the output signal 12 of the mixer 10 forms the desired intermediate frequency output signal which may further be converted to the desired television signal by a conventional intermediate frequency stage.
  • tuner 6 will be clarified with a numerical example, there being emphasized that the frequencies to be mentioned below, but also mentioned previously, are given merely for explanatory purposes and that the tuner according to the invention can be used in all those cases where there is a need for a tuner having such a large frequency range that cannot be covered at all or only in an economically unattractive manner with a conventional tuner.
  • the signal produced by the LNC 5 and having a frequency range from 950-2750 MHz is applied to the filters 7 and 8. It is assumed that the filter 7 has a tuning range from 950-1850 MHz and the filter 8 a tuning range from 1850-2750 MHz.
  • the transition frequency of 1850 MHz may also be, for example, 1750 or 2000 MHz. If the first terminal of mixer 10 is connected to the output of filter 7 via switch 9, the oscillator frequency is varied in a conventional manner from 1429.5 to 2329.5 MHz i.e. the second intermediate frequency, 479.5 MHz, above the 950-1850 MHz tuning range so as to convert this frequency band to the second intermediate frequency by implementing the double heterodyne principle.
  • the oscillator frequency is varied from 1370.5 to 2270.5 MHz i.e. the second intermediate frequency, 479.5 MHz, below the 1850-2750 MHz tuning range so as to convert this frequency band to the second intermediate frequency by implementing the single heterodyne principle.
  • the oscillator 11 needs to have only a frequency range from 1370.5-2329.5 MHz which can easily be realised with an oscillator comprising a varicap, so that still the whole frequency range from 950-2750 MHz can be covered.
  • Either of the tunable filters 7 and 8 has a limited frequency range too, so that these filters too can be realised simply and economically.
  • the television signal available in the frequency band from 1850-2750 MHz is inverted relative to the signal from the other, lower, frequency band which is converted in a conventional manner.
  • this problem may simply be solved by including an inverter circuit in the signal path downstream of the tuner, which inverter circuit is then only activated if filter 8 applies its output signal in the high-frequency band to the mixer 10.

Landscapes

  • Engineering & Computer Science (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Signal Processing (AREA)
  • Superheterodyne Receivers (AREA)
  • Input Circuits Of Receivers And Coupling Of Receivers And Audio Equipment (AREA)

Abstract

Syntoniseur haute fréquence à large bande conçu pour convertir des signaux dans une bande de radiofréquences comprise entre une fréquence f(1) et une fréquence f(2) en un signal de fréquence intermédiaire de fréquence fixe f(if). Ledit syntoniseur comporte un filtre passe-bande R.F. accordable, un oscillateur et un étage mélangeur qui présente une première entrée pour le signal de sortie du filtre passe-bande et une deuxième entrée pour un signal produit par l'oscillateur, le premier filtre passe-bande possédant une bande passante de f(1)-f(x), le deuxième filtre passe-bande possédant une bande passante de f(x)-f(2). De plus, des moyens de commutation permettent de connecter, au choix, le signal de sortie du premier ou du deuxième filtre passe-bande à la première entrée de l'étage mélangeur, l'oscillateur étant accordé sur une plage de fréquences comprise entre f(1)+f(if) et f(x)+f(if) si l'étage mélangeur est connecté au premier filtre passe-bande et sur une plage de fréquences comprise entre f(x)-f(if) et f(2)-f(if) si l'étage mélangeur est connecté au deuxième filtre passe-bande. En combinant les principes hétérodyne simple et double, on produit simplement un syntoniseur convenant à la réception satellite et possédant une gamme d'accord de 950 à 2750 Mhz, ce qui était, auparavant, impossible à couvrir avec un seul syntoniseur.
EP95901580A 1993-12-24 1994-12-14 Syntoniseur haute frequence a large bande Withdrawn EP0686318A1 (fr)

Priority Applications (1)

Application Number Priority Date Filing Date Title
EP95901580A EP0686318A1 (fr) 1993-12-24 1994-12-14 Syntoniseur haute frequence a large bande

Applications Claiming Priority (4)

Application Number Priority Date Filing Date Title
EP93203679 1993-12-24
EP93203679 1993-12-24
PCT/IB1994/000422 WO1995019074A2 (fr) 1993-12-24 1994-12-14 Syntoniseur haute frequence a large bande
EP95901580A EP0686318A1 (fr) 1993-12-24 1994-12-14 Syntoniseur haute frequence a large bande

Publications (1)

Publication Number Publication Date
EP0686318A1 true EP0686318A1 (fr) 1995-12-13

Family

ID=8214243

Family Applications (1)

Application Number Title Priority Date Filing Date
EP95901580A Withdrawn EP0686318A1 (fr) 1993-12-24 1994-12-14 Syntoniseur haute frequence a large bande

Country Status (3)

Country Link
EP (1) EP0686318A1 (fr)
JP (1) JPH08507431A (fr)
WO (1) WO1995019074A2 (fr)

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2810173A1 (fr) * 2000-06-08 2001-12-14 Thomson Multimedia Sa Dispositif d'emission et/ou de reception radiofrequence
WO2005101680A1 (fr) * 2004-04-19 2005-10-27 Koninklijke Philips Electronics N.V. Dispositif pour l'echange de signaux ultra large bande

Family Cites Families (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5823978B2 (ja) * 1975-11-11 1983-05-18 ソニー株式会社 チユ−ナ
US4234965A (en) * 1978-06-28 1980-11-18 Motorola, Inc. Communication tuning system utilizing local oscillator frequency selection for maximum RF filter bandwidth and method thereof
JPS5731235A (en) * 1980-08-01 1982-02-19 Hitachi Denshi Ltd Receiving system
AU2564992A (en) * 1991-09-26 1993-04-27 Thomson Consumer Electronics S.A. High frequency converter
FR2687029A1 (fr) * 1992-02-05 1993-08-06 Alcatel Telspace Recepteur superheterodyne large bande.

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
See references of WO9519074A3 *

Also Published As

Publication number Publication date
WO1995019074A2 (fr) 1995-07-13
JPH08507431A (ja) 1996-08-06
WO1995019074A3 (fr) 1995-08-31

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