Adaptive system for self-tuning and selecting a carrier frequency in a radio frequency communication system

• US 5,548,821 A
• Filed: 09/22/1994
• Issued: 08/20/1996
• Est. Priority Date: 06/09/1992
• Status: Expired due to Fees

• Current Assignee: Coveley, Michael
• Original Assignee: Coveley, Michael
• Inventors: Coveley, Michael
• Primary Examiner(s): Eisenzopf, Reinhard J.
• Assistant Examiner(s): Vo, Nguyen
• Application Number:
  US08/310,702
• Time in Patent Office: 698 Days
• Field of Search: 455/63, 455/67.1, 455/67.4, 455/68, 455/70, 455/71, 455/88, 455/182.3, 455/184.1, 455/185.1, 455/186.1, 455/193.1, 455/193.2, 455/193.3, 455/195.1 , 455/197.2, 455/336, 455/215, 455/50.1, 455/67.3, 455/296, 455/226.1, 455/34.1, 455/34.2, 455/62
• US Class Current: 455/67.14
• CPC Class Codes: H03D 11/04 by means of semiconductor devices having more than two electrodes
• CPC Class Codes: H03J 2200/15 Tuning of resonator by means of digitally controlled inductor bank
• CPC Class Codes: H03J 2200/28 Automatic self-alignment of a receiver

Abstract

A system for adaptive self-tuning of a receiver in a radio communication system. Prior to transmission of each data packet from a transmitter to a receiver, the transmitter generates a sequence of predefined test bytes (test sequence) n times at an initial carrier frequency. An identical version of the predefined test sequence is stored in the receiver. Circuitry is provided in the receiver for selected predefined states of tuning impedances for varying the center operating frequency of the receiver, wherein the predefined states of tuning impedances are equal in number to the predefined number of test sequences. A microcontroller in the receiver compares the received test sequence with the stored test sequence and creates a tuning table correlating respective states of the receiver tuning impedances with error bits detected in each state. The microcontroller then selects the tuning impedance state characterized by the least number of error bits, thereby selecting the optimal receiver center operating frequency to the initial carrier frequency generated by the transmitter. After the data has been transmitted by the transmitter at the initial carrier frequency and received by the receiver at the optimal center frequency, error detection is performed on the data. If the data has been received incorrectly, the transmitter changes its carrier frequency, the receiver changes its center frequency correspondingly, and the adaptive tuning test sequence is repeated.

Claims

1. For use with a transmitter adapted to transmit an information signal on an optimal one of a plurality of carrier frequencies and a receiver adapted to receive said information signal, a method for selecting said optimal one of said plurality of carrier frequencies and self-tuning said receiver relative to said optimal one of said carrier frequencies, comprising the steps of:

a) storing within said receiver a plurality of test sequences;

b) generating within said transmitter and transmitting identical versions of said plurality of test sequences at one of said plurality carrier frequencies;

c) selecting within said receiver respective ones of a predetermined number of tuning impedances equal in number to said plurality of test sequences for tuning said receiver to receive respective ones of said test sequences at respective centre operating frequencies in a narrow frequency band around said one of said plurality of carrier frequencies;

d) comparing within said receiver said test sequences received at said respective centre operating frequencies with said test sequences stored within said receiver, determining which one of said tuning impedances results in a least mismatch between said received test sequences and said stored test sequences, and selecting said one of said tuning impedances for receiving said information signal at an associated one of said centre operating frequencies which is optimally matched with said one of said plurality of carrier frequencies;

e) generating within said transmitter said information signal at said one of said plurality of carrier frequencies;

f) receiving within said receiver said information signal at said associated one of said centre operating frequencies and detecting whether said information signal has been correctly received, and in the event said information signal has been correctly received transmitting an acknowledgement signal to said transmitter, and in the event said information signal has not been correctly received monitoring for a subsequent transmission from said transmitter at a further one of said plurality of carrier frequencies;

g) detecting within said transmitter the presence of said acknowledgement signal from said receiver, and

i) in the event of detection of said acknowledgement signal then confirming the selection of said one of said plurality of cartier frequencies as said optimal carrier frequency, and

ii) in the event of an absence of detection of said acknowledgement signal then selecting said further one of said plurality of cartier frequencies and repeating steps b) through g).