Frequency filter controlled by pulse trains

Claim 2

A frequency filter responsive to control pulses the repetition rate of which selects the characteristic frequency of the filter, comprising: first and second line conductors connected to corresponding first and second input terminals (e1, e2) of the filter; energy storage means (C1, C2; C01, C02; C03, C04, C01hconnected to said first line conductor; and switching means (Sa, Sb; S2, S3, S4) connected to said first line conductor within said filter and with the corresponding energy storage means, said switch means being operated by the control pulses to complete a circuit for effecting pulse-type energy exchanges in said associated energy storage means within said filter, the rate of operation of said switch means being a function of the repetition rate of said control pulses and determinative of the characteristic frequency of the filter.

Claim 3

A frequency filter as recited in claim 1 wherein there is further provided: induction means (La, Lb; included in said energy exchange circuit; and said switching means Sa, Sb; S2, S3, S4) is actuated in response to the control pulses to complete a resonant circuit including said induction means (La, Lb; L) and said associated energy storage means (C, C02, C03, C04) for a time interval equal to one-half the period of the resonant frequency of the resonant circuit for effecting a complete energy exchange.

Claim 4

A frequency filter as recited in claim 2 wherein: said induction means is operative as a parametric amplifier to compensate for energy losses occurring in said filter.

Claim 5

A frequency filter as recited in claim 1 wherein there is further provided: supplemental energy storage means (C11, C12) connected in a parallel circuit with said energy storage means (C01, C02) of said filter; said parallel circuit including an amplifier element T12) connected to said energy storage means (C01, C02) and operative during intervals between pulse energy exchanges therein to supply said supplemental energy storage means (C11, C12) with a charge corresponding to that of said energy storage means (C01, C02); and said supplemental energy storage means (C11, C12) providing a charge during a pulse energy exchange in said energy storage means to compensate for energy losses in said filter during the pulse energy exchange.

Claim 6

A frequency filter as recited in claim 1 wherein: said energy storage means are connected in shunt between said first and second line conductors; and said switching means are connected in circuit in said first line conductor and operated in response to the control pulses to complete a circuit through said first line conductor for effecting the pulse-type energy exchanges in said corresponding energy storage means within said filter, the rate of operation of said switch being a function of the repetition rate of said control pulses and determinative of the characteristic frequency of the filter. 34

Claim 7

A frequency filter as recited in claim 5 wherein: said energy storage means comprises first and second capacitors (C1, C2; C01, C02); and said switching means comprises first and second switches (sa, Sb) connected in series circuit in said first line conductor, said first switching means (Sa) being connected between the connections of said first and second capacitors (C1, C2; C01, C02) to said first line conductor.

Claim 8

A frequency filter as recited in claim 6 wherein: said first and second line conductors define an output side of said filter remote from said input terminals (e(e1, E2) thereof, and there is further provided: a short circuit connection between said first and second line conductors at said output side of said filter.

Claim 9

A frequency filter as recited in claim 5 wherein there is further provided: first and second supplemental capacitors (C11, C12) connected in parallel circuit with said first and second storage capacitors (C01, C02), respectively; each of said parallel circuits including an amplifier element (T11, T12) connected to said associated storage capacitor (C01, C02) and operative during intervals between pulse energy exchanges therein to supply said supplemental capacitor (C11, C12) with a charge corresponding to that of said associated storage capacitor (C01, C02); and each of said supplemental capacitors (C11, C12) providing a charge during a pulse energy exchange in said respectively associated storage capacitor (C01, C02) to compensate for energy losses in said filter during the pulse energy exchange.

Claim 10

A frequency filter as recited in claim 8 wherein: each of said supplemental capacitors has a capacitance value equal to that of the respectively associated storage capacitor.

Claim 11

A frequency filter as recited in claim 8 wherein: at least selected ones of said supplemental capacitors have a capacitance value exceeding that of the respectively associated storage capacitors. 11. A frequency filter as recited in claim 1 wherein: said energy storage means comprises a principal capacitor (C01h) and a plurality of auxiliary capacitors (C02, C03, C04); and said switch means comprises a plurality of switches (S2, S3, S4) corresponding to said plurality of auxiliary capacitors (C02, C03, C04), each of said switches being operative in response to control pulses to independently complete a circuit for effecting pulse-type energy exchanges between said principal capacitor (C01h) and each of said plurality of auxiliary capacitors (C02, C03, C04).

Claim 12

A frequency filter as recited in claim 11 wherein: said line conductors define an output side of said filter remote from said input terminals (e 1, E2) thereof; said principal capacitor (C01h) is connected in shunt between said first and second line conductors at said output side of said filter; said plurality of corresponding switches S2, S3, S4) and auxiliary capacitors (C02, C03, C04) are connected in a corresponding plurality of series circuits; Said plurality of series circuits are connected in parallel in said first line conductor, between said first input terminal and the connection to said first line conductor of said principal capacitor (C01h); and a said switches (S2, S3, S4) are operated during individual tie time intervals to produce pulse-type energy exchanges between said principal capacitor (C01h); and each of said auxiliary capacitors (C02, C03, C04).

Claim 13

A frequency filter as recited in claim 12 wherein: said first and second line conductors define first and second output terminals at the output side of said filter; and utilization means (V) is connected to a said output terminals to receive an output signal from said frequency filter.

Claim 14

A frequency filter as recited in claim 11 wherein: said principal capacitor (C01h) is connected in shunt between said first and second input terminals, said corresponding plurality of switches (S2, S3, S4) and auxiliary capacitors (C02, C03, C04) are connected in a corresponding plurality of series circuits, said plurality of series circuits are connected in parallel and in shunt between said first and second line conductors; and said switches (S2, S3, S4) are operated in response to the control pulses to complete circuits for producing pulse-type exchanges between said principal capacitor (C01h) and each of said auxiliary capacitors (C02, C03, C04).

Claim 15

A frequency filter as recited in claim 11 wherein there is further provided: auxiliary switching means (S21, L2; S31, L3; S41, L4) respectively associated with said auxiliary capacitors (C02, C03, C04) and operative during intervals intermediate the intervals of switching of the respectively corresponding switches (S2, S3, S4) to effect a reversal of the polarity of the charge in said respectively associated auxiliary capacitors (C02, C03, C04). 16 A frequency filter as recited in claim 15 wherein; each of said auxiliary switching means comprises an auxiliary switch (S21, S31, S41) and an auxiliary inductor (L2, L3, L4) connected in a series circuit in parallel with said respectively associated auxiliary capacitor (C02, C03, C04); and each of said auxiliary switches (S21, S31, S41) is operative in response to a control pulse occurring during a time interval between successive actuations of the corresponding series connected switch (S2, S3, S4) of the respectively associated auxiliary capacitor (C02, C03, C04) to complete a resonant circuit of said respectively associated auxiliary capacitor (C02, C03, C04) and auxiliary inductor (C02, L2; C03, L3; C04, L4) to effect the charge polarity reversal. 17 A frequency filter as recited in claim 16 wherein: each of said auxiliary switches (S21, S31, and S41) is closed to complete the resonant circuit for an interval one-half the period of the resonant frequency of the resonant circuit.

Claim 16

A frequency filter as recited in claim 1 wherein: said energy storage means comprises a plurality of storage capacitors, each of said plurality of storage capacitors having the same capacitance value.

Claim 17

A frequency filter as recited in claim 1 wherein: said energy storage means comprises a plurality of storage capacitors; selected ones of said storage capacitors being of different capacitance values and effecting a reflection of the charge during a pulse charge exchange therebetween in accordance with the factor: wherein c1 and c2 represent the capacitance value of the storage capacitors supplying and receiving a charge, respectively, during a pulse charge exchange.

Claim 18

A frequency filter as recited in claim 1 wherein there is further provided: means (G) for applying amplitude modulated signal in impulses to said input terminals of said filter.

Claim 19

A frequency filter as recited in claim 20 wherein said sub supplying means comprises a connection channel of a time multiplex signalling system.

Claim 20

A frequency filter as recited in claim 1 wherein: said energy storage means comprises a plurality of capacitors (C1, C2); and said switching means (Sa, Sb) comprises a plurality of switches connected in said first line conductor for completing said energy exchange circuits between respectively associated capacitors, adjacent switches (Sa, Sb) being controlled during simultaneous time intervals and switches separated in said line conductor by an odd number of other switches being controlled during different time intervals in response to the control pulses.