| CPC H04W 56/0045 (2013.01) | 17 Claims |
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1. An apparatus for detecting group delay information over frequency for a transmission medium, comprising:
a receiver for receiving a measurement signal to provide a reception signal, the measurement signal comprising at least a first carrier signal at a first carrier frequency, a second carrier signal at a second carrier frequency and a third carrier signal at a third carrier frequency, wherein transmission phase information on the carrier signals are known or derivable;
a frequency analyzer for analyzing the reception signal to acquire reception phase information on the first carrier signal, the second carrier signal and the third carrier signal; and
a processor
for forming a first combined piece of phase information from the reception phase information from a first pair of carrier signals and for forming a second combined piece of phase information from the reception phase information from a second pair of carrier signals, the second pair of carrier signals differing from the first pair of carrier signals,
for forming a first piece of group delay information from the first combined piece of phase information and the transmission phase information relating to the first pair of carrier signals and for forming a second piece of group delay information from the second combined piece of phase information and the transmission phase information relating to the second pair of carrier signals, and
for associating the first piece of group delay information to a first frequency and the second piece of group delay information to a second frequency, the first frequency being derived from frequencies of the first pair of carrier signals, and the second frequency being derived from frequencies of the second pair of carrier signals,
wherein the transmission medium is a coaxial infrastructure in which a bandwidth of the reception signal is between 50 MHz and 500 MHz, in which a measurement region of the coaxial infrastructure starts at a frequency of greater than or equaling 1000 MHz and ends at a frequency of smaller than or equaling 5000 MHz, and wherein a length of the coaxial infrastructure is greater than 50 m,
or
wherein the transmission phase information for one carrier signal of the first carrier signal, the second carrier signal and the third carrier signal comprise a phase of + or −90 degrees and, for another carrier signal of the first carrier signal, the second carrier signal and the third carrier signal, a phase of 0 or 180 degrees, and wherein the processor is configured to use a value of 180 degrees as a phase threshold or a correction threshold,
or
wherein the reception signal comprises a number of further carrier signals in addition to the first carrier signal, the second carrier signal and the third carrier signal, which are spaced in frequency over a carrier signal spacing, the number being at least 30, and wherein the frequency analyzer is configured to calculate a phase value for each carrier signal as a piece of reception phase information,
or
wherein the transmission phase information comprise a first transmission difference between the second carrier signal and the first carrier signal and a second transmission difference between the second carrier signal and the third carrier signal, wherein the frequency analyzer is configured to acquire a first reception phase value for the first carrier signal, a second reception phase value for the second carrier signal and a third reception phase value for the third carrier signal, wherein the processor is configured to calculate a reception difference from the first reception phase value and the second reception phase value as the first combined piece of phase information, and to calculate a second reception difference from the second reception phase value and the third reception phase value as the second combined piece of phase information, wherein the processor is configured to calculate the first piece of group delay information from the first reception difference and the first transmission difference, and to calculate the second piece of group delay information from the second reception difference and the second transmission difference, and wherein the processor is configured to calculate an uncorrected first reception difference from the first reception phase value and the second reception phase value, and to calculate an uncorrected first transmission difference from a first transmission phase value for the first carrier signal and a second transmission phase value for the second carrier signal, and to perform a phase correction in case the uncorrected first reception difference or the uncorrected first transmission difference is greater than a correction threshold,
or
wherein the receiver is configured to convert a first frequency section to a base band using a first local oscillator frequency, and to convert a second frequency section to the base band using a second local oscillator frequency, wherein the receiver is controlled to set the first local oscillator frequency and the second local oscillator frequency to be temporally offset using a fixed schedule or a schedule received via a side channel, and wherein the first local oscillator frequency and the second local oscillator frequency are set such that the first frequency section and the second frequency section overlap in an overlap region so that several pieces of group delay information each are acquired from measurements with different local oscillator frequencies for carrier frequencies in the overlap region, and wherein the receiver is configured to perform a single-sideband demodulation using the first local oscillator frequency and the second local oscillator frequency, wherein the first frequency section is arranged in frequency below the first local oscillator frequency, wherein the second frequency section is arranged in frequency below the second local oscillator frequency, and wherein the receiver is configured to convert a third frequency portion to the base band using a third local oscillator frequency, wherein the third frequency portion is arranged above the third local oscillator frequency, the third local oscillator frequency being higher than the first local oscillator frequency or smaller than the second local oscillator frequency, the second frequency portion and the third frequency portion overlapping with each other,
or
wherein the receiver is configured to convert a first frequency section to a base band using a first local oscillator frequency, and to convert a second frequency section to the base band using a second local oscillator frequency, wherein the receiver is controlled to set the first local oscillator frequency and the second local oscillator frequency to be temporally offset using a fixed schedule or a schedule received via a side channel, and wherein the first local oscillator frequency and the second local oscillator frequency are set such that the first frequency section and the second frequency section overlap in an overlap region so that several pieces of group delay information each are acquired from measurements with different local oscillator frequencies for carrier frequencies in the overlap region, wherein the processor is configured to modify group delay information outside the overlap region for the first frequency portion or the second frequency portion using the group delay information for the different local oscillator frequencies in the overlap region to reduce or eliminate discontinuities due to different local oscillator frequencies, and wherein the processor is configured to calculate a first mean value from group delay information of the first frequency portion in the overlap region to form a second mean value from group delay information of the second frequency portion in the overlap region, to calculate a correction value using the first mean value and the second mean value, and to combine the correction value with the group delay information of the first frequency portion or the second frequency portion to acquire corrected group delay information as the first or the second piece of group delay information.
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