Combination hybrid and switching circuit and method utilizing resonant transfer

Claim 2

A combination hybrid and switching circuit for a two-way communications system having a plurality of lines and hybrid transmit and receive paths to be selectively connected to said lines and comprising: a plurality of electric charge storage devices designed for operation in a resonant transfer mode and connected one in each said line and in each said path; common bus means connecting said paths; series connected resonant transfer line and path gates connected between each line device and each path device and said bus means; and means closing and opening said gates at a sampling frequency equal to at least two times the highest line frequency of interest and sequentially operating said line gates to place their closure periods in spaced time slots occuring within the sampling period and with only one line closed at a time, and closing and opening said path gates in sequence with their closure periods timed for resonant transfer and the closure of said receive path gate occurring as closely following as possible without significant overlap after the opening of said transmit path gate, and providing synchronized closing of selected line and path gates.

Claim 3

A circuit as defined in claim 1, the closing period of said line gates being at least equal to the time required for, and including periods of, successive closures of said path gates.

Claim 4

A circuit as defined in claim 1 having a plurality of hybrid transmit and receive paths, said bus means comprising: a first bus connecting each of said transmit paths; a second bus connecting each of said receive paths; a pair of said line gates being connected in parallel to each said line device and connected one to said first bus and the other to said second bus; and, said gate operating means providing synchronized operation of a selected one of said pairs of gates with the transmit and receive paths of a selected hybrid.

Claim 5

The circuit as defined in claim 1 and having a plurality of hybrid transmit and receive paths, said path devices comprising bandpass filters having passbands distributed at multiples of said sampling frequency and being connected to provide frequency division multiplexing of said paths.

Claim 6

The circuit of claim 4, each of said line devices comprising a lowpass filter.

Claim 7

A circuit as defined in claim 4: a common transmit channel connected to the outputs of said bandpass filters in said transmit paths; and, a common receive channel connected to the inputs of said bandpass filters in said receive paths.

Claim 8

The circuit of claim 6: an amplifier having an input connected to said filter outputs in said transmit path and an output connected to said common transmit channel; and, an amplifier having an input connected to said common receive channel and an output connected to said inputs of said receive path filters.

Claim 9

The circuiT of claim 7: and, terminating resistors connected one between each transmit path and the input of said first named amplifier, and one between each receive path and the output of said second named amplifier.

Claim 10

A first terminal comprising the circuit of claim 6; a second terminal having a plurality of second lines and second common receive and transmit channels connected to said first named transmit and receive channels, respectively; a plurality of second bandpass filters having passbands corresponding with said first named bandpass filters and being connected to said second channels; a plurality of second lowpass filters designed for operation in a resonant transfer mode with said second bandpass filters and connected one in each second line; common bus means connecting said second lowpass filters; series connected resonant transfer line and path second gates connected between each second lowpass filter and each second bandpass filter and said bus means; and, means closing and opening said second gates at a sampling frequency equal to at least two times the highest line frequency of interest and sequentially operating said second line gates to place their closure periods in spaced time slots occurring within the sampling period and with only one second line gate closed at a time, and closing and opening said second path gates in sequence with their closed periods timed for resonant transfer and the closure of said second receive path gates occurring as closely following as possible without significant overlap after the opening of said transmit path gates, and providing synchronized closing of selected second line and second path gates.

Claim 13

The method defined in claim 10 wherein said terminal is provided with a plurality of hybrid transmit and receive paths; and, providing separate common bus connections for said transmit and receive paths.

Claim 14

The method defined in claim 10 wherein said terminal is provided with a plurality of hybrid transmit and receive paths; selecting passbands for at least certain of said transmit and receive path filters which differ from each other by multiples of said sampling frequency; and, connecting said paths to provide frequency division multiplexing.

Claim 15

The method defined in claim 12. connecting the outputs of said bandpass filters in said transmit paths to a common transmit channel; and, connecting the inputs of said passband filters in said receive paths to a common receive channel.

Claim 16

The method as defined in claim 12: connecting second common receive and transmit channels of a second terminal to said first named transmit and receive channels, respectively; connecting to said second common channels a plurality of second bandpass filters having passbands corresponding to said first named bandpass filters; effecting hybrid separation of a plurality of second terminal lines by resonant transfer between second line filters and said second bandpass fIlters by sampling gates having a sampling frequency of at least two times the highest line message frequency of interest; providing a common connection between said second lines and second paths; operating said second line gates to place their closure periods in spaced time slots occurring within the sampling period and with only one second line closed at a time; closing and opening said second path gates in sequence with their closed periods timed for resonant transfer with the closure of said second receive path gates occurring as closely following as possible without significant overlap after the opening of said transmit path gates; and, synchronizing the closing of selected second line and second path gates.