Method and apparatus for determining communications link quality and receiver tracking performance
AssigneeHughes Aircraft Company
InventorU. A. von der Embse
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Abstract
Apparatus is disclosed for measuring a receiver measurement data set, and a digital processor adapted to determine a derived data set indicative of the communications link quality and dynamic receiver performance, utilizing powerful data reduction algorithms. The invention allows the monitoring of the quality and performance of remote communications links employing a communications receiver, determining the input signal amplitude and noise level, the carrier power to noise power density, the receiver tracking loop phase bias and 1-sigma jitter.
Claims34
In a remote receiver/transmitter station for receiving a communication signal modulated with data from a first station, the remote station being adapted to demodulate the signal and retransmit it to a second station, the improvement wherein the remote station further comprises:
- measuring means for measuring a receiver measurement data set comprising readily measurable parameters selected from at least one of the following four parameters:
- a first parameter indicative of an estimate of the amplitude of said communication signal, a second parameter indicative of an estimate of the incident noise level, a third parameter indicative of the receiver average tracking phase error, and a fourth parameter indicative of the receiver RMS phase error;
- digital processor means connected to the measuring means for processing said receiver measurement data set into a derived data set including at least one data value selected from the following five data values:
- a first data value indicative of the signal amplitude of said communication signal, a second data value indicative of the received noise power level, a third data value indicative of the signal carrier to noise power density, a fourth data value indicative of the tracking performance of the receiver, and a fifth data value indicative of the random phase tracking error of the receiver;
- and
- means for transmitting the demodulated signal and said derived data set to said second station whereby the second station can obtain information about the communication link quality and receiver performance in addition to the communication signal.
A method for determining the quality of a communications link employing a communications signal and a remote communications receiver, comprising the steps of:
- (1) providing a measuring means in the remote receiver for measuring a receiver measurement data set comprising readily measurable parameters selected from at least one of the following four parameters:
- a first parameter indicative of an estimate of the amplitude of said communication signal, a second parameter indicative of an estimate of the out-of-band noise level, a third parameter indicative of the receiver average tracking phase error, and a fourth parameter indicative of the receiver RMS phase error;
- (2) instructing a digital processor means coupled to the measuring means to calculate, from said measurement data set, a derived data set indicative of the quality of said communications link including at least one data value selected from the following five data values:
- a first data value indicative of the signal amplitude of said communication signal, a second data value indicative of the received noise power level, a third data value indicative of the signal carrier to noise power density, a fourth data value indicative of the tracking performance of the receiver, and a fifth data value indicative of the random phase tracking error of the receiver;
- and
- (3) transmitting the derived data set together with a signal associated with the communications signal to a ground station whereby the ground station can obtain information about the communication link quality and receiver performance in addition to the communication signal.
An improved communications link, comprising:
- a transmitted data signal modulated with data;
- a receiver dapated to receive and demodulate said signal to recover said data, said receiver including a discrete Fourier transform (DFT) filter bank and a phase lock loop (PLL) phase discriminant;
- measuring means in said receiver and coupled to the DFT filter bank and PLL phase discriminant for measuring receiver parameters and providing a measurement data set indicative of characteristics of said transmitted signals;
- digital processor means in the receiver and coupled to said measuring means and adapted to calculate a derived data set from said measurement data set to provide an indication of communication link and receiver performance;
- and
- utilization means adapted to utilize said derived data set.
Dependencies are inferred from the claim text.