Shared-Antenna FM Transceiver Using DDFS for Simultaneous Tx/Rx

Solution Overview

Problem

Existing systems face challenges in integrating multiple audio communication technologies into a single portable device, such as Bluetooth and FM radios, due to the need for separate processing hardware and software, which increases power consumption and design complexity, and requires sophisticated power management to maximize battery life.

Innovation Solution

A method and system for simultaneous FM transmission and reception using a shared antenna and a direct digital frequency synthesizer (DDFS), which generates signals corresponding to the difference between transmission and reception frequencies to enable simultaneous operation via a single chip with integrated Bluetooth and FM radios, minimizing the need for separate processing hardware and optimizing power usage.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If separate processing hardware and software are used for multiple audio communication technologies, then each technology can be implemented independently, but device complexity and power consumption increase

Engineering Contradiction:

Improvemulti-audio communication capabilityVSAvoidprocessing hardware complexity

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent combines multiple audio communication technologies (FM radio, Bluetooth, audio processing) into a single integrated chip. The chip includes an FM receiver, Bluetooth module, audio processor, and DDFS sharing common components such as the antenna, crystal oscillator, and digital signal processing resources, eliminating the need for separate processing hardware for each technology.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The DDFS (Direct Digital Frequency Synthesizer) is designed to serve multiple functions: generating carrier frequencies for FM transmission, providing clock signals for the Bluetooth module, and supplying reference frequencies for the audio processor. This multi-functional approach reduces the overall number of frequency generation circuits needed in the device.

Inventive Principle:

Principle #6Universality (Multi-functionality)

2Adaptability or versatility

If separate processing hardware and software are used for multiple audio communication technologies, then each technology can be implemented independently, but power consumption increases

Engineering Contradiction:

Improvemulti-audio communication capabilityVSAvoidpower consumption

Core Design Contradiction:

Adaptability or versatilityVSUse of energy by moving object

Solution Approach 1:

The patent combines multiple audio communication technologies (FM radio, Bluetooth, audio processing) into a single integrated chip. The chip includes an FM receiver, Bluetooth module, audio processor, and DDFS sharing common components such as the antenna, crystal oscillator, and digital signal processing resources, eliminating the need for separate processing hardware for each technology.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The DDFS (Direct Digital Frequency Synthesizer) is designed to serve multiple functions: generating carrier frequencies for FM transmission, providing clock signals for the Bluetooth module, and supplying reference frequencies for the audio processor. This multi-functional approach reduces the overall number of frequency generation circuits needed in the device.

Inventive Principle:

Principle #6Universality (Multi-functionality)

3Adaptability or versatility

If simultaneous FM transmission and reception are implemented, then audio communication flexibility is improved, but signal interference and processing complexity increase

Engineering Contradiction:

Improveaudio communication flexibilityVSAvoidprocessing overhead

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent introduces a bi-directional coupler as an intermediary component between the antenna and the FM transmitter/receiver. This coupler enables simultaneous transmission and reception by directing transmitted and received signals through different paths, preventing direct interference while allowing the antenna to serve both functions concurrently.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent replaces traditional analog frequency synthesis and signal processing mechanisms with a Direct Digital Frequency Synthesizer (DDFS) and digital signal processing. The DDFS generates precise frequency signals digitally, and the audio processor handles signal conditioning and modulation/demodulation in the digital domain, reducing processing overhead and improving simultaneous operation capability.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Data Source

PatentUS7925222B2Method and system for simultaneous FM transmission and FM reception using a shared antenna and a direct digital frequency synthesizer

Publication Date: 2011.04.12 NXP USA INC

AI summary

Certain aspects of a method and system for simultaneous FM transmission and FM reception using a shared antenna and a direct digital frequency synthesizer (DDFS) may be disclosed. In a FM transceiver that receives FM signals at a frequency f1 and transmits FM signals at a frequency f2, aspects of the method may include generating via a DDFS, a signal corresponding to a difference between f1 and f2 to enable simultaneous transmission and reception of FM signals via shared antenna.