Switched active fault locate filter
AssigneeRC Concepts, Inc.
InventorsAlbert H. Miller, Maynard A. Wright
Life of this patent
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Abstract
In locating a faulty regenerator, a fault locating filter is used in a T1 or T1C Carrier Repeater Apparatus Case or Office Repeater Bay (ORB) to select the appropriate fault locate sinusoid from the output winding of the repeater. This process uses three different filter types at twelve different frequencies. Conventional filter design requires a different filter for each frequency leading to the need to stock 36 different filters. This patent covers the design of a filter which may be optioned to provide all three types and twelve frequencies within a single unit, reducing the required inventory of such filters by a substantial amount.
Claims13
In a telephone network having a plurality of regenerators, a fault locate filter, comprising:
- a constant gain amplifier providing a constant gain amplified signal matched to a plurality of test frequencies wherein an input signal comprises a selected one of the test frequencies;
- a phase-locked loop detecting the selected test frequency in the amplified signal;
- and
- a switch controlled by the phase-locked loop wherein only detection of the selected frequency causes the switch to be activated so as to gate the amplified signal onto a test line, wherein the input signal is received from a T-carrier line.
A method of bandpass filtering an input signal, comprising the steps of:
- amplifying and clipping the input signal;
- detecting a frequency in the input signal;
- locking the detected frequency;
- and
- providing the input signal as an output when the detected frequency is locked.
A fault locating filter in a telephone network, comprising:
- means for phase-locking a signal, the phase-locking means having means for detecting a predetermined frequency of the signal;
- a switch controlled by the phase-locking means, the switch receiving the signal and selectively passing the signal when the predetermined frequency is detected by the phase-locking detecting means;
- and
- means connected to the switch for controlling the output amplitude and phase of the signal.
Dependencies are inferred from the claim text.