Multiband Circuit Configuration for Attenuation Compensation
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Solution Overview
Problem
Existing multi-band circuit arrangements for mobile radio devices face challenges in attenuating signal paths to and from external antennas, particularly with the close frequency spacing between GSM1800 and UMTS standards, leading to crosstalk and increased circuit complexity.
Innovation Solution
A multi-band capable circuit arrangement with multiple receiver and power amplifiers, frequency filters, and frequency-selective switching means that detects transmission signals to selectively activate appropriate circuit parts for GSM or CDMA-based standards, avoiding crosstalk by bypassing frequency band filters and ensuring reliable attenuation compensation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If frequency band filters (diplexers) are used to separate GSM and UMTS signals, then multi-band operation is enabled, but crosstalk occurs between GSM1800 and UMTS circuits due to close frequency spacing
Solution Approach 1:
The patent implements dynamic switching between different circuit configurations based on the detected transmission signal type. The circuit transitions between a first switching state (GSM mode with diplexer) and a second switching state (UMTS mode without diplexer), allowing optimal operation for each standard while avoiding crosstalk by activating the appropriate configuration only when needed
Solution Approach 2:
The patent changes the circuit configuration parameters dynamically - specifically, the switching state of the diplexer and circuit parts is changed based on the detected transmission signal. When a GSM transmission signal is detected, the circuit switches to a state where the diplexer is active; when no GSM signal is detected, the diplexer is deactivated, thereby adapting the circuit parameters to match the operating standard
2Reliability
If diplexers are implemented to prevent crosstalk between GSM1800 and UMTS, then signal isolation is improved, but circuit complexity and component volume increase disproportionately
Solution Approach 1:
Instead of maintaining a complex diplexer-based isolation structure continuously, the patent dynamically activates the diplexer only when GSM signals are present. This temporal separation of functions allows simpler overall circuit design while maintaining signal isolation reliability when needed, avoiding the permanent complexity of full-duplex diplexer implementations
3Reliability
If separate circuit parts are provided for GSM and UMTS operation, then standard-specific optimization is achieved, but the circuit cannot handle simultaneous transmissions on both standards
Solution Approach 1:
The patent uses dynamic switching to transition between different operational modes - single-standard GSM mode, single-standard UMTS mode, and full-duplex UMTS mode. This allows the circuit to optimize performance for the active standard while maintaining the capability to handle UMTS full-duplex operations, achieving versatility through temporal multiplexing rather than simultaneous parallel processing
Data Source
AI summary
The invention relates to a multiband-capable circuit arrangement for compensating the attenuation of an antenna feed cable to an external antenna for a mobile communication device. The circuit arrangement consists of several receive amplifiers, several power amplifiers, frequency filters, and several units for detecting a transmit signal from the mobile communication device operated by the circuit arrangement, as well as electrical or electronic switching elements actuated by these detector units. In the absence of a transmit signal from the mobile communication device operated by it, it assumes a basic circuit state in which the reception of mobile communication signals according to both the GSM standard and a CDMA-based mobile communication standard is enabled, and the power amplifiers are de-energized.Upon detection of a transmission signal from the mobile device, the circuit arrangement switches to a switching state in which, depending on the frequency of the detected transmission signal, either the transmission of mobile signals of a frequency of the GSM standard or the transmission and reception of mobile signals according to a CDMA-based mobile communication standard via the external antenna is enabled, and only the power amplifier intended for amplifying signals with the corresponding frequency is switched on.