EP0146339A2
Expired / Lapsed
EP
⏱️ 0.0 years remaining
Electrical signal separating device having isolating and matching circuitry
Assignee: BSH Industries Ltd
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Filing: 1984-12-12
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Granted: —
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Expires: 2004-12-12
Abstract
Abstract An electrically heatable window of a motor vehicle can be used as an efficient VHF receiving aerial. Isolating circuitry, which may include one or more bifilar coils (L1, L2) is used to separate RF signals from the heater D.C. power supply circuit, and matching circuitry is used to match the window heating element to an aerial input impedance of an aerial feeder circuit of the radio receiver. In one embodiment, the matching circuitry (L3, C5) is such as to give series resonance near the centre of the VHF band. In a second embodiment the matching circuitry (L1, Ca) is such as to give parallel resonance near the centre of the VHF band. In a third embodiment the matching circuitry (L1, C1, L3, C2) is such as to give resonance in two passbands near the centre of the VHF band. The third embodiment can be used for transmitting as well as receiving.
Inventors
- 👤 Jerzy Jacek Kropielnicki
- 👤 James David Last
- 👤 Brian Easter
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-26 09:45
CPC Classifications
H; H03; H03H; H03H7/00; H03H7/38; H01; H01Q; H01Q1/00; H01Q1/12; H01Q1/1271; H01Q1/1278
Claims Analysis
Total Claims: 15
Claim 1
Independent Claim
165 words
An isolating and matching device to enable a heating element of a motor vehicle electrically heatable window, not designed specifically to be an aerial and essentially aperiodic and non-resonant at RF frequencies, to be used as a receiving aerial, said device having input leads for connection to a motor vehicle D. C. power supply, output leads for connection to said heating element, an aerial terminal for connection to an aerial feeder circuit of a receiver, isolating circuitry coupled with said input and output leads and operable to permit passage of D.C. power from said input leads to said output leads while isolating or blocking passage of RF signals from said output leads to said input leads, and aerial matching circuitry interposed between said output leads and said aerial terminal characterised in that said matching circuitry is operable to effectively match the impedance of the said heating element to an aerial input impedance of the said aerial feeder circuit thereby to effect efficient VHF signal reception.
Claim 2
Dependent Claim
165 words
An isolating and matching device to enable a heating element of a motor vehicle electrically heatable window, not designed specifically to be an aerial and essentially aperiodic and non-resonant at RF frequencies, to be used as a receiving aerial, said device having input leads for connection to a motor vehicle D. C. power supply, output leads for connection to said heating element, an aerial terminal for connection to an aerial feeder circuit of a receiver, isolating circuitry coupled with said input and output leads and operable to permit passage of D.C. power from said input leads to said output leads while isolating or blocking passage of RF signals from said output leads to said input leads, and aerial matching circuitry interposed between said output leads and said aerial terminal characterised in that said matching circuitry is operable to effectively match the impedance of the said heating element to an aerial input impedance of the said aerial feeder circuit thereby to effect efficient VHF signal reception.
Claim 3
Dependent Claim
47 words
A device according to claim 1 characterised in that said matching circuitry comprises input circuitry (L3, C5) connected with said isolating circuitry (Ll, L2) and to said output leads and operable to bring the said heating element to series resonance near the centre of the VHF band.
Claim 4
Dependent Claim
46 words
A device according to claim 1 characterised in that said matching circuitry comprises inout circuitry (Ll, Ca) incorporating an inductance (Ll) of the said isolating circuitry (Ll, L2) and operable to bring the said heating element to parallel resonance near the centre of the VHF band.
Claim 5
Dependent Claim
22 words
A device according to claim 2 or 3, characterised in that said matching circuitry further includes a parallel resonant circuit (L4, C7).
Claim 6
Independent Claim
25 words
A device according to any one of claims 2 to 4, characterised in that said isolating circuitry includes at least one bifilar coil (Ll, L2).
Claim 7
Independent Claim
34 words
A device according to any one of claims 2 to 4, characterised in that said isolating circuitry includes a toroidal or U-shaped core wound with two mutually coupled coils of equal but opposite polarity.
Claim 8
Dependent Claim
25 words
A device according to claim 4, characterised in that a VHF band amplifier (TR2, FET T2) is connected with said parallel resonant circuit (L4, C7).
Claim 9
Dependent Claim
28 words
A device according to claim 7, characterised in that an AM band amplifier (TR3, FET T3) is also provided to afford reception of AM signals by said receiver.
Claim 10
Dependent Claim
27 words
A device according to claim 8, characterised in that a bias-supply circuit (Dl, Tl, R3, R5) is provided for said VHF band and AM band amplifier. -
Claim 11
Dependent Claim
55 words
A device according to claim 1 for use in conjunction with a VHF transmitter as well as a receiver,- characterised in that said matching circuitry comprises a circuit (Ll, Cl, L3, C2) for providing two VHF passbands, one centred on a predetermined VHF transmit frequency and the other centred on a predetermined VHF receive frequency.
Claim 12
Dependent Claim
34 words
A device according to claim 10, characterised in that an inductor (Ll) of said isolating circuit is used to bring the said heating element to parallel resonance near the centre of the VHF band.
Claim 13
Dependent Claim
39 words
A device according to claim 10 or 11, characterised in that said matching circuit includes a first series resonator (Cl), and a second series resonator (L3, C2), operable to produce series resonance near the centre of the VHF band.
Claim 14
Dependent Claim
42 words
A device according to claim 12, characterised in that said matching circuit includes series resonant circuits ( L4 , C 3 and L5, C4) for providing two VHF passbands respectively at a predetermined VHF transmit frequency and a predetermined VHF receive frequency.
Claim 15
Dependent Claim
39 words
A device according to claim 13, characterised in that said two series resonant circuits (L4, C3, L5, C4) are connected in parallel with each other and connected between said second series resonator (L3, C2) and said aerial feeder circuit.
References Cited (Backward Citations)
No citation records indexed.
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