Complementary Binary Signal Codes for Zero Secondary Maxima

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Solution Overview

Problem

Existing binary coded signal technologies face limitations in achieving optimal pulse compression and detection due to the presence of secondary maxima in autocorrelation functions, especially for longer code lengths, leading to misdetection and cross-talk issues.

Innovation Solution

The use of complementary binary signal codes, where one sequence is transmitted and the other generated in the receiver, allows for the cancellation of secondary maxima in the autocorrelation function, enabling optimal pulse compression and improved detection by doubling the bit length iteratively, and utilizing symmetry properties for perfect correlation-matched filters.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If binary Barker codes are used for signal transmission, then the main-to-secondary maxima ratio is improved (N:1), but the code length is limited to N≤13

Engineering Contradiction:

Improvemain-to-secondary maxima ratioVSAvoidcode length

Core Design Contradiction:

Measurement precisionVSLength of moving object

Solution Approach 1:

The code is divided into two complementary sequences (first and second sequences) that are processed separately through autocorrelation, and their results are combined to cancel secondary maxima while allowing longer code lengths

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent combines two complementary binary sequences to form a composite coding scheme that achieves both long code length and zero secondary maxima by summing their autocorrelation functions

Inventive Principle:

Principle #40Composite materials

2Productivity

If longer binary codes (N>13) are used to increase code length, then productivity is improved, but interfering secondary maxima appear in the AKF causing misdetection

Engineering Contradiction:

Improvecode lengthVSAvoiddetection accuracy

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The patent converts the harmful secondary maxima into beneficial cancellation by using complementary sequences where the secondary maxima of one sequence are equal in magnitude but opposite in sign to those of the other sequence, causing them to cancel when summed

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

Solution Approach 2:

The complementary sequence acts as a counterweight to the primary sequence, with its autocorrelation function providing equal but opposite secondary maxima that cancel the harmful interference when combined

Inventive Principle:

Principle #8Anti-weight (Counterweight)

3Adaptability or versatility

If PN sequences are used for synchronous data transmission, then adaptability is improved, but large secondary maxima (≥√2N) cause disturbances and cross-talk

Engineering Contradiction:

Improvesynchronous data transmission capabilityVSAvoidcross-talk

Core Design Contradiction:

Adaptability or versatilityVSObject-generated harmful factors

Solution Approach 1:

The patent transforms the large secondary maxima problem by using complementary sequences where the secondary maxima cancel each other, converting the harmful cross-talk potential into a benefit of zero secondary maxima and reduced interference

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

Data Source

PatentUS8423598B2Circuit arrangement and method for receiving specially designed coded signals

Publication Date: 2013.04.16 RUDERSHAUSEN REINHART

AI summary

In order to attain an optimally compressed, narrow pulse peak at the filter output of a correlation filter for the purpose of reception, the interfering secondary maxima of the autocorrelation function of binary codes must be as small as possible. The invention uses specially designed signal codes which are used to generate the associated complementary signal code from the received sequence by means of evaluation in the reception filter. The subsequent parallel formation of the autocorrelation functions of the received signal code and the complementary signal code exhibits secondary maxima having an opposite mathematical sign, thus resulting in the desired prefect pulse peak having secondary maxima which are equal to zero during summation at the filter output.