Communication system using low bandwidth wires
First Claim
1. A method for reconstruction of a reference signal transmitted in a communications system between a master unit having a master local oscillator and a remote unit having a remote local oscillator, the master and remote units connected by conductive wires, the reference signal being transmitted over the conductive wires together with a signal which is down-converted from an original high frequency signal to an intermediate frequency signal at the master unit and up-converted back into the original high frequency signal at the remote unit, the method comprising:
- at the master unit, embedding the reference signal as a carrier of a management signal using a master modem;
transmitting the management signal with the embedded reference signal over the conductive wires to the remote unit;
at the remote unit, reconstructing the reference signal from the management signal using a phase locked loop (PLL), wherein the PLL comprises a phased detector, a charge pump, a voltage controlled crystal oscillator and a capacitor; and
using the reconstructed reference signal for synchronizing the remote local oscillator with the master local oscillator,wherein the management signal comprises a management data bit stream and wherein the step of reconstructing the reference signal from the management signal further comprises using a charge pump shutter coupled to the PLL and synchronized with the management data bit stream to keep the reconstructed reference signal stable.
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Accused Products
Abstract
A high frequency signal is down-converted into an intermediate frequency signal, transmitted over a limited bandwidth medium from a master unit to a remote unit and up-converted back into its original high frequency at the remote unit. The up-conversion is aided by reconstruction of a reference signal embedded at the master unit as a carrier for a management signal which is transmitted to the remote unit through the same limited bandwidth medium together with the intermediate frequency signal. The reference signal is reconstructed using a phase locked loop which includes a charge pump and is kept stable during intervals between bits and messages by a charge pump shutter.
1086 Citations
20 Claims
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1. A method for reconstruction of a reference signal transmitted in a communications system between a master unit having a master local oscillator and a remote unit having a remote local oscillator, the master and remote units connected by conductive wires, the reference signal being transmitted over the conductive wires together with a signal which is down-converted from an original high frequency signal to an intermediate frequency signal at the master unit and up-converted back into the original high frequency signal at the remote unit, the method comprising:
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at the master unit, embedding the reference signal as a carrier of a management signal using a master modem; transmitting the management signal with the embedded reference signal over the conductive wires to the remote unit; at the remote unit, reconstructing the reference signal from the management signal using a phase locked loop (PLL), wherein the PLL comprises a phased detector, a charge pump, a voltage controlled crystal oscillator and a capacitor; and using the reconstructed reference signal for synchronizing the remote local oscillator with the master local oscillator, wherein the management signal comprises a management data bit stream and wherein the step of reconstructing the reference signal from the management signal further comprises using a charge pump shutter coupled to the PLL and synchronized with the management data bit stream to keep the reconstructed reference signal stable. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. A method for reconstruction of a reference signal transmitted in a communications system between a master unit having a master local oscillator and a remote unit having a remote local oscillator, the master and remote units connected by conductive wires, the reference signal being transmitted over the conductive wires together with a signal which is down-converted from an original high frequency signal to an intermediate frequency signal at the master unit and up-converted back into the original high frequency signal at the remote unit, the method comprising:
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at the master unit, embedding the reference signal as a carrier of a management signal using a master modem; transmitting the management signal with the embedded reference signal from a first duplexer over the conductive wires to an input duplexer in the remote unit; separating the transmitted management signal with the embedded reference signal from the first duplexer by frequency band at the input duplexer; at the remote unit, reconstructing the reference signal from the management signal using a phase locked loop (PLL); and using the reconstructed reference signal for synchronizing the remote local oscillator with the master local oscillator, wherein the management signal comprises a management data bit stream and wherein the step of reconstructing the reference signal from the management signal further comprises using a charge pump shutter coupled to the PLL and synchronized with the management data bit stream to keep the reconstructed reference signal stable. - View Dependent Claims (9, 10, 11)
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12. A system for reconstructing a reference signal transmitted in a distributed communications system over electrically conductive wires between a master unit having a master local oscillator and a remote unit having a remote local oscillator, the system comprising:
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a master modem configured to embed the reference signal at the master unit as a carrier of a management signal carrying a management data bit stream and management messages between the master unit and the remote unit; a first duplexer configured to transfer the management signal to an input duplexer in the remote unit; a phase locked loop (PLL) for reconstructing the reference signal at the remote unit, the reconstructed reference signal used to synchronize the master and remote local oscillators; and a charge pump shutter for keeping the reconstructed reference signal stable during intervals between the management data bit stream and management messages. - View Dependent Claims (13, 14, 15, 16, 17, 18, 19)
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20. A system for reconstructing a reference signal transmitted in a distributed communications system over electrically conductive wires between a master unit having a master local oscillator and a remote unit having a remote local oscillator, the system comprising:
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a master modem configured to embed the reference signal at the master unit as a carrier of a management signal carrying a management data bit stream and management messages between the master unit and the remote unit; a first duplexer configured to transfer the management signal to an input duplexer in the remote unit; and a phase locked loop (PLL) for reconstructing the reference signal at the remote unit, the reconstructed reference signal used to synchronize the master and remote local oscillators, wherein the PLL comprises a charge pump, a voltage controlled crystal oscillator and a capacitor configured to reconstruct the reference signal, and wherein the PLL has a lock time designed to be faster by a factor of at least two than the period of a management data bit.
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Specification