Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
100 words
A vehicle radio receiver system comprising: an antenna (1); a receiver (17); cable means (15) connecting the antenna (1) to the receiver (17); and a matching circuit (25) between said antenna (1) and said cable means (15), characterised in that: a reactance (C 4 ) of said antenna (1) and a reactance (Cε) of said cable means (15) constitute elements of said matching circuit (25); and the matching circuit (25) is arranged to have input and output resistances substantially matching the output resistance (Ri) of the antenna (1) and the input resistance (R 2 ) of the receiver (17) respectively.
Claim 2
Dependent Claim
100 words
A vehicle radio receiver system comprising: an antenna (1); a receiver (17); cable means (15) connecting the antenna (1) to the receiver (17); and a matching circuit (25) between said antenna (1) and said cable means (15), characterised in that: a reactance (C 4 ) of said antenna (1) and a reactance (Cε) of said cable means (15) constitute elements of said matching circuit (25); and the matching circuit (25) is arranged to have input and output resistances substantially matching the output resistance (Ri) of the antenna (1) and the input resistance (R 2 ) of the receiver (17) respectively.
Claim 3
Dependent Claim
57 words
A system according to Claim 1 wherein said matching circuit (25) has a transfer function, T(f) where f is frequency, such that: for all frequencies within a selected frequency band, where V 1 is the voltage from said antenna (1), k is a constant and V 2 the voltage developed at the input to said receiver (17).
Claim 4
Dependent Claim
16 words
A system according to Claim 2 wherein said selected frequency band is 100 to 2000 KHz.
Claim 5
Dependent Claim
55 words
A system according to Claim 1 or Claim 2 or Claim 3 wherein said reactance (C 4 ) of said antenna (1) is the capacitance (C 4 ) of said antenna to ground and said reactance (Cs) of said cable means (15) is the capacitance (C 6 ) of said cable means (15) to ground.
Claim 6
Independent Claim
22 words
A system according to any one of the preceding claims wherein said matching circuit (25) includes a series inductor (L 3 ).
Claim 7
Dependent Claim
26 words
A system according to Claim 5 wherein said matching circuit (25) includes a resistor (R A ) in series with said series inductor (L 3 ).
Claim 8
Independent Claim
22 words
A system according to any one of the preceding claims wherein said matching circuit (25) includes a parallel inductor (L 4 ).
Claim 9
Dependent Claim
24 words
A system accprdlng to Claim 7 wherein said matching circuit (25) includes a resistor (R B ) in parallel with said parallel Inductor (L4).
Claim 10
Independent Claim
23 words
A system according to any one of the preceding claims wherein said antenna (1) comprises a rear window electric heater of the vehicle.
Claim 11
Dependent Claim
46 words
A system according to Claim 9 wherein said matching circuit (25) includes at least one radio frequency isolation inductor (Li, L 2 ) via which said rear window electric heater is connected to the vehicle battery (13) for the supply of electric current for heating purposes.
Claim 12
Dependent Claim
37 words
A system according to Claim 9 or Claim 10 wherein said matching circuit (25) includes at least one capacitor (C l ) which serves to prevent direct current from the vehicle battery (13) reaching said receiver (17).