Two stage surge protection for single wire multi switch transceiver

Abstract

An architecture for protecting circuitry used for signal communications between a frequency translation module (20) and a decoder (60) from transient voltage surges. According to an exemplary embodiment, the apparatus comprises a first signal path between a transmission line and a first reference potential, comprising a high impedance negative surge path; and a second signal path between the transmission line and the first reference potential, comprising a high impedance positive surge path, a low inductance surge path and a DC blocker circuit, wherein said high impedance positive surge path is configured in series with said low inductance surge path and said DC blocker circuit, wherein each of said low inductance surge path and said DC blocker circuit are coupled between said high impedance positive surge path and said source of reference potential.

Description

RELATED APPLICATION[0001]This application claims the benefit of U.S. Provisional Application No. 60 / 920,055 filed Mar. 26, 2007, which is hereby incorporated by reference.BACKGROUND OF THE INVENTION[0002]1. Field of the Invention[0003]The present invention generally relates to signal communications, and more particularly, to architecture for integrating and protecting a single wire multi switch (SWM) transceiver and the legacy LNB mode into the same satellite set top box.[0004]2. Background Information[0005]In a satellite broadcast system, one or more satellites receive signals including audio and / or video signals from one or more earth-based transmitters. The satellite(s) amplify and rebroadcast these signals to signal receiving equipment at the dwellings of consumers via transponders that operate at specified frequencies and have prescribed bandwidths. Such a system includes an uplink transmitting portion (i.e., earth to satellite(s)), an earth-orbiting satellite receiving and tra...

AI Technical Summary

Benefits of technology

[0013]In accordance with an aspect of the present invention, an apparatus is provided. The apparatus comprises a first signal path between a transmission line and a first reference potential, comprising a high impedance negative surge path; and a second signal path between the transmission line and the first reference potential, comprising a high impedance positive surg

Problems solved by technology

However, a problem arises when multiple circuits are coupled to the RF conductor of the coaxial cable where each circuit is required to perform a different task.

The low impedance of the 20V DC power supply may short the 2.3 MHz tone to ground and result in 2.3 MHz SWM failure.

An additional concern arises in that the 2.3 MHz SWM tone could cause harmonics to arise on the shared RF cable.

These harmonics may interrupt other working systems on the shared RF cable.

If such a voltage is applied on surge protection diode or a transistor b-e junction, harmonic could occur on the RF coax cable and affects other working unit on same conductor.

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