Automatic cable loss compensation
First Claim
1. A communication system, comprising:
- a transceiver (T/R) adapted to be coupled to an antenna for receiving and demodulating first signals received from the antenna and generating second signals for transmission back to the antenna;
an amplifier coupled to receive the second signals from the T/R and configured, in response thereto, to amplify the second signals and supply amplified second signals to the antenna for emission therefrom;
a test signal source coupled to receive a link compensation initiate signal and configured, in response thereto, to generate an RF test signal of known signal strength;
a detector coupled to receive the RF test signal and measure the received signal strength;
an electronically variable attenuator disposed between the T/R and the amplifier and adapted to modify signal attenuation from the T/R to the amplifier; and
one or more processors for comparing the known signal strength and the received signal strength and setting the variable attenuator so that the signal attenuation from the T/R to the amplifier, including signal attenuation in the RF link and signal attenuation in the variable attenuator, has a predetermined value.
1 Assignment
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Accused Products
Abstract
Method and apparatus are provided for compensation of an RF link between a transmitter and amplifier of a communication system. The apparatus comprises a signal source coupled to the transmitter for providing an RF test signal of a first magnitude to the RF link, a test signal measuring apparatus at the RF input of the amplifier for measuring a second magnitude of the test signal reaching the RF input of the amplifier through the RF link, and an electronically adjustable attenuator serially coupled with the RF link and responsive to differences between the first and second magnitudes so as to provide attenuation in an RF communication signal passing into the amplifier from the RF link such that the sum of RF signal loss in the link and the attenuator has a predetermined value.
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Citations
20 Claims
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1. A communication system, comprising:
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a transceiver (T/R) adapted to be coupled to an antenna for receiving and demodulating first signals received from the antenna and generating second signals for transmission back to the antenna;
an amplifier coupled to receive the second signals from the T/R and configured, in response thereto, to amplify the second signals and supply amplified second signals to the antenna for emission therefrom;
a test signal source coupled to receive a link compensation initiate signal and configured, in response thereto, to generate an RF test signal of known signal strength;
a detector coupled to receive the RF test signal and measure the received signal strength;
an electronically variable attenuator disposed between the T/R and the amplifier and adapted to modify signal attenuation from the T/R to the amplifier; and
one or more processors for comparing the known signal strength and the received signal strength and setting the variable attenuator so that the signal attenuation from the T/R to the amplifier, including signal attenuation in the RF link and signal attenuation in the variable attenuator, has a predetermined value. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. A method for compensating an RF communication link of a communication system, comprising:
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sending a test signal of known initial strength through the RF communication link to an amplifier input port;
comparing a received strength of the test signal at the input port to the initial strength;
determining the path loss of signal strength through the RF communication link; and
automatically setting a variable attenuator serially coupled to the communication link so that the combination of the path loss and attenuation loss has a predetermined value. - View Dependent Claims (11, 12, 13, 14, 15)
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16. An RF communication system having a transmitter-amplifier combination compensated for variable coupling loss, wherein the transmitter has an RF signal output and a control signal input and the amplifier has an RF signal input, the combination comprising:
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a signal source coupled to the transmitter for providing in response to a loss compensation initiation signal received at the control signal input of the transmitter, an RF test signal of a first magnitude to the RF signal output of the transmitter;
a lossy transmission medium having an input coupled to the RF signal output of the transmitter and an output coupled to the RF signal input of the amplifier;
a test signal measuring apparatus coupled between the output of the lossy transmission medium and the RF signal input of the amplifier for measuring a second magnitude of the test signal reaching the RF signal input of the amplifier through the lossy transmission medium; and
an electronically adjustable attenuator serially coupled with the lossy transmission medium and responsive to differences between the first and second magnitudes so as to provide an attenuation in an RF communication signal passing into the amplifier from the lossy transmission medium such that the sum of RF communication signal loss in the lossy medium and in the attenuator has a predetermined value. - View Dependent Claims (17, 18, 19, 20)
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Specification