Wireless Transmitter Local Oscillator Segmentation for Power Efficiency

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Solution Overview

Problem

Conventional wireless communication devices face challenges in reducing power consumption while maintaining a variable frequency range and ensuring proper reception of radio signals, especially after erroneous synchronization due to thermal or radio wave noise, which affects battery life and reliability.

Innovation Solution

A wireless transmitter/receiver system with a local oscillator using a frequency multiplier circuit for power-efficient frequency conversion, combined with a phase locked loop circuit for wide frequency range, and an operation controller that intermittently checks signal strength to optimize power usage and prevent unnecessary consumption.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a phase locked loop circuit is used as a local oscillator, then a wide variable frequency range is achieved, but power consumption increases

Engineering Contradiction:
Improvevariable frequency rangeVSAvoidpower consumption
Core Design Contradiction:
Adaptability or versatilityVSUse of energy by moving object

Solution Approach 1:

The local oscillator is divided into two independent circuits: a PLL circuit for frequency synthesis and a frequency multiplier circuit for frequency multiplication. This segmentation allows selective use of each circuit based on operational requirements, enabling wide frequency range when needed while reducing power consumption during normal operation.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent dynamically switches between the PLL circuit and frequency multiplier circuit based on the required frequency range. The system adapts its oscillator configuration in real-time, using the PLL for wide frequency coverage and the frequency multiplier for power-efficient operation within a specific range.

Inventive Principle:
Principle #15Dynamics

2Reliability

If the operation controller continuously operates, then reliable signal reception is ensured, but power consumption increases and battery life decreases

Engineering Contradiction:
Improvesignal reception reliabilityVSAvoidpower consumption
Core Design Contradiction:
ReliabilityVSUse of energy by moving object

Solution Approach 1:

The operation controller is designed to operate intermittently rather than continuously. It periodically wakes up to check for incoming signals by monitoring the RF amplifier output, then returns to sleep mode. This periodic operation maintains signal reception capability while significantly reducing average power consumption.

Inventive Principle:
Principle #19Periodic action

Solution Approach 2:

The system uses the existing RF amplifier and mixer components to perform signal detection during sleep mode without requiring full controller operation. The RF amplifier continuously monitors the frequency band, and the mixer converts signals to intermediate frequency, allowing the controller to detect presence of signals with minimal power consumption.

Inventive Principle:
Principle #25Self-service

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

The system achieves reduced power consumption while securing a variable frequency range and ensuring reliable radio signal reception, thereby extending battery life and improving communication reliability.

Implementation Method 1

a first frequency conversion unit and a second frequency conversion unit which convert a reference oscillation signal having a reference oscillation frequency outputted from an output terminal of the reference oscillation unit into the local oscillation signal

Methodology Applied
Scientific EffectFrequency multiplication:

Implementation Method 2

the first frequency conversion unit includes a frequency multiplying circuit having power consumption smaller than that of the phase locked loop circuit

Methodology Applied
Scientific EffectPhase locked loop frequency synthesis:

Implementation Method 3

a mixer for mixing a local oscillation signal having the local oscillation frequency outputted from an output terminal of the local oscillator and a radio signal received by an antenna and converting the same into a signal having a frequency (intermediate frequency) lower than that of the RF signal

Methodology Applied
Scientific EffectFrequency mixing: Heterodyne

Data Source

PatentEP2541994B1Wireless transmitter/receiver, wireless communication device, and wireless communication system
Publication Date: 2017.09.27 PANASONIC INTELLECTUAL PROPERTY MANAGEMENT CO LTD
  • EP2541994B1 patent drawingFigure 1
  • EP2541994B1 patent drawingFigure 2
  • EP2541994B1 patent drawingFigure 3A~4B

AI summary

Disclosed is a wireless transmitter/receiver provided with: a local oscillator which oscillates at a predetermined local oscillator frequency; a mixer which mixes a local oscillation signal of the local oscillation frequency outputted from an output terminal of the local oscillator and a radio signal received by an antenna; a modulation circuit which modulates the local oscillator signal and generates a radio signal; and a transmission/reception switching unit which selectively switches over between a reception state in which the output terminal of the local oscillator is connected to the mixer and a transmission state in which the output terminal is connected to the antenna without passing through the mixer.