Tone signal switching system

Claim 2

Signal routing switching apparatus comprising switch means having a plurality of switch positions, tone signal generator means operative in response to the actuation of said switch means to selected switch positions to produce first and second component tone signals representative of each of said selected switch position, a plurality of local oscillators respectively operative to produce at their respective outputs, local oscillator signals corresponding to each of said tone signals producible by said tone signal generator means, a plurality of demodulators respectively corresponding to each of said tone signals producible by said tone signal generator means, each of said demodulators having first and second input and an output, the output of each of said local oscillators being respectively connected to said first input of the corresponding demodulator and the output of said tone signal generator being connected to each of said second input of said demodulators, a plurality of AND gates respectively corresponding to said selected switch positions, each of said AND gates having first and second inputs respectively connected to the output of the demodulator which corresponds to the first and second tone signals representing the selected switch position.

Claim 3

Signal routing switching apparatus as defined in claim 1 wherein said first and second component tone signals are substantially coincident in time.

Claim 4

Signal routing switching apparatus as defined in claim 1 wherein the respective frequencies of said local oscillator signals respectively differ from the frequencies of the tone signals producible by said tone generator means by a preselected frequency.

Claim 5

Signal routing switching apparatus as defined in claim 3 wherein each of said demodulators comprises mixer means having first and second inputs for the application thereto respectively of the corresponding local oscillator signal and the corresponding tone signal, said mixer means being operative to produce at its output a difference frequency signal of a frequency equal to said preselected frequency, I.F. amplifier means having its input connected to the output of said mixer means for amplifying said difference frequency signal, inverter means having its input connected to the output of said I.F. amplifier means for inverting said difference frequency signal, and detector means having first and second inputs respectively connected to the outputs of said I.F. amplifier means and said inverter means for the application thereto of said difference frequency and inverted difference frequency signals and operative to produce in response thereto a dc., signal which is applied to the corresponding AND gates.

Claim 6

Signal routing switching apparatus for a plurality of user control stations comprising switch means having a plurality of switch positions at each of said user control stations, tone signal generator means at each of said user control stations, each of said tone signal generator means being operative in response to the actuation of said switch means at the corresponding user control station to a selected switch position, to produce first and second component tone signals representative of each of saId selected switch positions, a plurality of local oscillators respectively operative to produce at their respective outputs, local oscillator signals corresponding to each of said tone signals producible by said tone signal generator means, a bank of demodulators at each of each user control stations, said demodulators in each of said banks respectively corresponding to each of said tone signals producible by said tone signal generator means, each of said demodulators in a bank having first and second inputs and an output, the outputs of said local oscillators being respectively commonly connected to the said first input of the corresponding demodulator at each of said user control stations and the output of each said tone signal generator means being connected to each of said second inputs of the demodulators at the corresponding user control station, and a bank of AND gates ate each of said suer control stations, said AND gates respectively corresponding to said selected switch positions at its user control station, each of said AND gates at a user control station having first and second inputs respectively connected to the outputs of the demodulators at said user control station which correspond to the first and second tone signals representing the selected switch position.

Claim 7

Signal routing switching apparatus for a plurality of user control stations comprising switch means having a plurality of switch positions at each of said user control stations, tone signal generator means at each of said user control stations, each of said tone signal generator means being operative in response to the actuation of said switch means at the corresponding user control station to a selected switch position, to produce first and second component tone signals representative of each of saId selected switch positions, a plurality of local oscillators respectively operative to produce at their respective outputs, local oscillator signals corresponding to each of said tone signals producible by said tone signal generator means, a bank of demodulators at each of each user control stations, said demodulators in each of said banks respectively corresponding to each of said tone signals producible by said tone signal generator means, each of said demodulators in a bank having first and second inputs and an output, the outputs of said local oscillators being respectively commonly connected to the said first input of the corresponding demodulator at each of said user control stations and the output of each said tone signal generator means being connected to each of said second inputs of the demodulators at the corresponding user control station, and a bank of AND gates ate each of said suer control stations, said AND gates respectively corresponding to said selected switch positions at its user control station, each of said AND gates at a user control station having first and second inputs respectively connected to the outputs of the demodulators at said user control station which correspond to the first and second tone signals representing the selected switch position.

Claim 8

Signal routing switching apparatus as defined in claim 5 wherein said first and second component tone signals are substantially coincident in time.

Claim 9

Signal routing switching apparatus as defined in claim 5 wherein the respective frequencies of said local oscillator signals respectively differ from the frequencies of the tone signals producible by said tone generator means by a preselected frequency.

Claim 10

Signal routing switching apparatus as defined in claim 7 wherein each of said demodulators comprises mixer means having first and second inputs for the application thereto respectively of the corresponding local oscillator signal and the corresponding tone signal, said mixer means being operative to produce at its output a difference frequency signal of a frequency equal to said preselected frequency, I.F. amplifier means having its input connected to the output of said mixer means for amplifying said difference frequency signal, inverter means having its input connected to the output of said I.F. amplifier means for inverting said difference frequency signal, and detector means having first and second inputs respectively connected to the outputs of said I.F. amplifier means and said inverter means for the application thereto of said difference frequency and inverted difference frequency signals and operative to produce in response thereto a dc. signal which is applied to the corresponding AND gates.