Classifications

• • H—ELECTRICITY
  • H03—ELECTRONIC CIRCUITRY
  • H03J—TUNING RESONANT CIRCUITS; SELECTING RESONANT CIRCUITS
  • H03J5/00—Discontinuous tuning; Selecting predetermined frequencies; Selecting frequency bands with or without continuous tuning in one or more of the bands, e.g. push-button tuning, turret tuner
  • H03J5/24—Discontinuous tuning; Selecting predetermined frequencies; Selecting frequency bands with or without continuous tuning in one or more of the bands, e.g. push-button tuning, turret tuner with a number of separate pretuned tuning circuits or separate tuning elements selectively brought into circuit, e.g. for waveband selection or for television channel selection
  • H03J5/242—Discontinuous tuning; Selecting predetermined frequencies; Selecting frequency bands with or without continuous tuning in one or more of the bands, e.g. push-button tuning, turret tuner with a number of separate pretuned tuning circuits or separate tuning elements selectively brought into circuit, e.g. for waveband selection or for television channel selection used exclusively for band selection
  • H03J5/244—Discontinuous tuning; Selecting predetermined frequencies; Selecting frequency bands with or without continuous tuning in one or more of the bands, e.g. push-button tuning, turret tuner with a number of separate pretuned tuning circuits or separate tuning elements selectively brought into circuit, e.g. for waveband selection or for television channel selection used exclusively for band selection using electronic means

Definitions

• Circuit arrangement for generating a reverse voltage for
• the invention relates to a circuit arrangement for generating a blocking voltage for switching diodes for switching the resonance frequency in RF filter circuits by rectifying the oscillator vibrations generated in a receiver oscillator.
• the invention is therefore based on the object of circumventing this disadvantage and, despite the low circuit voltage, making it possible to generate a negative DC voltage from the oscillator vibrations in band 1. This object is achieved by the measure specified in the claim. Further advantageous embodiments of the invention are described in the subclaims.
• the input signal UE is applied via a bandpass filter 1 to a mixer stage 2, at the other input of which the oscillator signal Uo generated in an oscillator 3 is applied.
• the intermediate frequency signal UZF can be removed at the output of mixer stage 2.
• the filter circuits of the bandpass filter 1 and the oscillator circuit 4 of the oscillator 3 are by means of capacitance variation diodes 5, 6 and 7 via a tuning chip UA tunable.
• Switching diodes 8 and 9 are used for band switching of the filter circuits, which are either switched through by a switching voltage US or blocked by a voltage by applying a negative blocking voltage to the anodes.
• a rectifier diode 10 with a very small threshold voltage in the order of magnitude of 0.15 to 0.25 volts is used to generate the negative blocking voltage required in this example .
• a diode for example a Schottky diode, a negative direct voltage of 0.8 volts can be achieved.
• This diode 10 is connected with its cathode to the oscillator circuit coil 14. The anode is connected to reference potential via a capacitor 11.
• a switching voltage US can be supplied to the diode 10 via a resistor 15 and a contact 16.
• the resistor 15 is also connected to the reference potential via an RC element 17, at which the reverse voltage generated can be removed and fed to the switching diodes 8 and 9 in the HF filter circuits via the line 18.
• the diode 10 has a disadvantageous property in the form of a relatively high internal series resistance, which can be of the order of 10 ohms. This high resistance impedes the function of the oscillator in the band 2 operating mode, ie if the Schottky diode is switched through by a positive switching voltage US and bridges a circular coil 14 of the oscillator circuit 4. Therefore, as a further measure of the invention, a switching diode 12 is placed parallel to the Schottky diode 10.
• the anode of the diode 12 is connected to the reference potential via a capacitor 13.
• the S cha It voltage US is supplied to the diode 12 via a resistor 18.
• the diode 12 bridges the diode 10 with low resistance in the band 2 mode.
• This parallel-connected diode 12 consists, for example, of a silicon diode with a very low series resistance of the order of 0.8 ohms and with a relatively high forward voltage. That way The generation of the negative direct voltage by means of Schottky diode 10 for band 1 operation and, on the other hand, a low-impedance switching of the oscillator coil in band 2 operation by silicon diode 12.

Landscapes

• Inductance-Capacitance Distribution Constants And Capacitance-Resistance Oscillators (AREA)
• Electronic Switches (AREA)
• Filters And Equalizers (AREA)

Applications Claiming Priority (2)

Publications (1)

Family

ID=6400991

Family Applications (1)

Country Status (10)

Families Citing this family (1)

Family Cites Families (7)

• 1990
  • 1990-02-26 DE DE4006018A patent/DE4006018A1/de not_active Withdrawn
• 1991
  • 1991-02-15 JP JP3503974A patent/JPH05504247A/ja active Pending
  • 1991-02-15 AU AU72370/91A patent/AU7237091A/en not_active Abandoned
  • 1991-02-15 WO PCT/EP1991/000297 patent/WO1991013493A1/de not_active Application Discontinuation
  • 1991-02-15 HU HU922559A patent/HUT63715A/hu unknown
  • 1991-02-15 EP EP91903796A patent/EP0518876A1/de not_active Withdrawn
  • 1991-02-21 TR TR91/0156A patent/TR24648A/xx unknown
  • 1991-02-25 CN CN91101103.XA patent/CN1022156C/zh not_active Expired - Fee Related
• 1992
  • 1992-08-24 FI FI923795A patent/FI923795A0/fi not_active Application Discontinuation
  • 1992-09-14 US US07/988,604 patent/US5270579A/en not_active Expired - Lifetime

Non-Patent Citations (1)

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