Frequency discriminator apparatus

Claim 1

In frequency discriminator apparatus including input means for receiving FM signals, output means adapted to provide demodulated information signals thereat and first and second branch circuit means electrically connected between said input means and said output means, said first and second branch circuit means each comprising detector circuit means, wherein the improvement comprises: tuned circuit means in each of said first and second branch circuit means for applying FM signals from said input means to said detector circuit means, each of said tuned circuit means comprising; a first impedance circuit including three reactive elements electrically interconnected to form a two-terminal network, at least one of said reactive elements being inductive and the remainder of said three elements being capacitive, a pair of serially connected equal value resistance means connected in a shunting relationship across said first impedance circuit, and a second impedance circuit in the form of a two-terminal network connected between a junction formed intermediate said pair of serially connected equal value resistance meanS and a reference potential, said second impedance circuit in the form of a two-terminal network having an impedance value whose ratio with respect to the value of one of said resistance means is equal to the reciprocal of the ratio of the impedance value of said first impedance circuit with respect to one of said resistance means, said first and second impedance circuit means and said pair of equal value resistance means being connected to form a bridged T four-terminal network configuration, and a branching circuit means interposed between said input means and said first and second branch circuit means for coupling FM signals applied to said input means to said first and second branch circuit means, said branching circuit means exhibiting output impedances which are matched to the resistance means present in said four-terminal network configuration.