Broadband switch/coupler
AssigneeAT&T Corp.
InventorChristopher W Rice
Life of this patent
Estimating the term…
Abstract
Parallel combined redundancy and switched redundancy are provided for active RF devices (i.e., amplifiers) in a cable plant system with a switch/coupler circuit of passive magnetic devices and switches that respond to an amplifier failure by switching the circuit into a combined or switched redundancy mode as needed to maintain a suitable dynamic range of operation. In either redundancy mode, the switch/coupler circuit operates with a constant 3dB reduction of dynamic range.
Claims13
A method of providing backup for amplifier failure in a coaxial cable plant including a stage of paralleled first and second amplifiers, by the steps of:
- arranging for responding to a failure of one of the first and second amplifiers, by:
- balancing outputs of the first and second amplifier;
- converting the balanced output to an unbalanced state;
- and
- transforming the unbalanced state into an impedance transformer/transmission line state.
A broadband switch for coupling and decoupling RF amplifiers from a cable system, comprising;
- first and second inputs for receiving first and second RF amplifiers;
- a balancing network connected to the first and second inputs by first and second switch devices so as receive an output of a least one of the RF amplifiers and operative for balancing outputs of the first and second RF amplifiers;
- a balance-to-unbalance network connected for converting an output of the first and second RF amplifiers to an unbalanced output;
- and
- an impedance matching network for creating a matching impedance for connecting an output of the first and second RF amplifiers to a cable transmission medium.
A method of providing redundancy in provisioning of amplifiers in a cable system;
- comprising the steps of
- constraining a balance of first and second RF amplifier outputs with a first pair of magnetically coupled windings,
- unbalancing the balanced outputs of said first and second RF amplifier outputs with a second pair of magnetically coupled windings to produce an unbalanced amplified signal;
- selectively impedance matching the unbalanced output by adjusting an impedance level based on the number of operative RF amplifiers;
- and
- disconnecting a failed amplifier from the step of constraining balance.
Dependencies are inferred from the claim text.