Programmable Frequency Calibration for Multi-Standard Filter Tuning
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Solution Overview
Problem
Conventional frequency selecting elements in wireless communication systems face challenges in precision frequency selection due to variations in manufacturing parameters, temperature, and power supply voltage, leading to poor communication quality and increased chip area and cost in multi-standard systems.
Innovation Solution
A calibration apparatus comprising a basic reference source, programmable counter, control logic unit, and frequency to time constant converter with capacitors, transconductor, and comparator, which generates and tunes different frequency signals to achieve precise frequency calibration and response tuning, reducing the need for additional system costs and maintaining design specifications.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional frequency selecting elements are used without calibration, then the device complexity is low, but the manufacturing precision deteriorates due to parameter variations
Solution Approach 1:
The calibration apparatus performs frequency selection calibration before the actual operation of the frequency selecting element. The calibration process pre-determines the correct capacitor configuration to compensate for manufacturing variations, temperature drift, and power supply fluctuations, ensuring precise frequency selection without requiring complex real-time adjustment mechanisms during operation.
Solution Approach 2:
The calibration apparatus utilizes the existing basic reference source already present in the electronic system to generate calibration signals. By reusing the system's own reference source rather than introducing an external calibration signal generator, the apparatus achieves frequency calibration functionality while minimizing additional device complexity and cost.
2Adaptability or versatility
If multiple filters are used for multi-standard applications, then the adaptability is improved, but the area of stationary object increases
Solution Approach 1:
The calibration apparatus enables a single frequency selecting element to serve multiple frequency standards by providing programmable calibration that can be configured for different frequency requirements. The same hardware infrastructure (basic reference source, counter, capacitor array) supports calibration for various communication standards including GSM, CDMA, and WiFi, eliminating the need for separate dedicated filters for each standard.
Solution Approach 2:
The frequency selecting element incorporates a programmable calibration mechanism that can dynamically adjust its characteristics based on the required communication standard. The calibration apparatus stores calibration data for multiple standards and programmatically configures the capacitor array according to the active standard, allowing the same hardware to adapt its frequency response characteristics as needed.
3Ease of operation
If operation amplifier is used for higher order filter, then the ease of operation is improved, but the speed deteriorates due to insufficient bandwidth
Solution Approach 1:
The invention replaces the operation amplifier-based continuous-time filter mechanism with a calibration-based approach using a basic reference source, programmable counter, and capacitor array. This substitution eliminates the bandwidth limitations of operation amplifiers while maintaining the ease of higher-order filter implementation through programmable control logic that can generate complex filter responses through calibrated RC circuits.
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
Enables precise frequency selection capabilities, reduces chip area and cost, and provides a digital interface for configuring frequency responses in multi-standard applications, overcoming variations in process, temperature, and power supply.
Implementation Method 1
the transadmittance filter uses a transconductor 205 to convert the voltage signals, Vin and Vin_, into current signals, to charge and discharge the capacitor C
Implementation Method 2
the filter uses two switches 207, 208 for switching between capacitors C1, C2, and controlling the charging and discharging to form the frequency selection mechanism
Data Source
AI summary
Disclosed is a calibration apparatus and method for programmable response frequency selecting elements. The calibration apparatus comprises a basic reference source, a programmable counter, a control logic unit, and a frequency to time constant converter. The programmable counter generates plural different frequency signals required by the frequency selecting elements with different frequency responses. The frequency to time constant converter determines a calibrated capacitance through the timing control signals generated by the control logic unit. This invention makes the process, temperature, and power supply variation for frequency selecting elements free. It allows the frequency selecting elements to have a high accurate, stable, and wide range programming of frequency responses. It is suitable for multi-standard applications. It greatly reduces the chip size, and significantly lowers down the cost for the applications.