Patent ID: 8295323

Claim:
A method for synchronization of transmitted and received signals in frequency hopping communication systems where data is transmitted in frames comprising a preamble and a data block, the frequency hopping communication system comprising a transmitter and a receiver, two PN-generators, one located at a transmitting end and one located at a receiving end, both generating a same predefined frequency pattern causing the transmitter and the receiver to hop in frequency according to the same predefined frequency pattern, the receiver and the PN-generator at the receiving end also being part of a synchronization unit, the method comprising: slowing a clock rate in the receiver with respect to a clock rate of the transmitter, thus causing an interference pattern comprising a characteristic pattern and a reversed characteristic pattern, wherein the characteristic pattern and the reversed characteristic pattern result from interference between the predefined frequency pattern of the transmitted signal and a slowed down predefined frequency pattern used in the receiver, the slowed down predefined frequency pattern being controlled by the slower clock rate in the receiver and used in the receiver during synchronization, and a measure of a delay between the transmitted data and received signals being defined as a time elapsed from start of synchronization represented by a starting point, the synchronization being initiated by a start sync signal, until obtaining the characteristic patterns being a measure of the delay between the transmitted data and received signals which is used to synchronize the receiver to the transmitted signals; and receiving the predefined frequency pattern of the transmitted signal in the receiver with a first delay proportional to a distance between the receiver and transmitter, wherein the characteristic pattern starts at a synchronization point in the interference pattern at the time tc after a second delay, wherein a Vernier scale effect causes the second delay, and wherein the second delay is a measure of the delay between the transmitted and received signal, to be magnified compared to the first delay.