Method and arrangement for radiocommunication using a band-spreading technique
First Claim
1. An system for radio communication comprising:
- a transmitter operating in the GHz range and transmitting a signal inputted thereto in a spread-spectrum manner using a plurality of periods of a PN sequence;
a receiver comprised ofa receiving circuit;
a multiplying circuit having two inputs;
a low-pass filter having a time constant approximately equal to a time corresponding to the time needed for a number of complete PN sequences of said transmitter, wherein the receiver supplies at one input of said multiplying circuit and a spread-spectrum signal internally generated at said receiver is supplied to the other input of said multiplying circuit and wherein the output of said multiplying circuit is supplied to said low-pass filter.
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Accused Products
Abstract
The invention relates to a method and an arrangement for radiocommunication between a transmitter and a receiver, especially transmission of information between mobile units and/or fixed units in connection with monitoring and controlling traffic. A problem with this type of communication arises when a single wave is reflected from the roadway or ground and this wave is of approximately the same strength as the direct wave between transmitter and receiver. According to the invention, the problem is overcome by using communication at high frequencies, the GHz range, and using a spread-spectrum technique. By utilizing a spread-spectrum technique, the relative distance and relative speed between transmitter and receiver can also be calculated by simple means, which is a special advantage in this application (FIG. 2 a).
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Citations
9 Claims
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1. An system for radio communication comprising:
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a transmitter operating in the GHz range and transmitting a signal inputted thereto in a spread-spectrum manner using a plurality of periods of a PN sequence; a receiver comprised of a receiving circuit; a multiplying circuit having two inputs; a low-pass filter having a time constant approximately equal to a time corresponding to the time needed for a number of complete PN sequences of said transmitter, wherein the receiver supplies at one input of said multiplying circuit and a spread-spectrum signal internally generated at said receiver is supplied to the other input of said multiplying circuit and wherein the output of said multiplying circuit is supplied to said low-pass filter. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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Specification