Transmitter Linearity Built-In-Self-Test Circuit
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Solution Overview
Problem
Existing methods for testing transceiver circuits require extensive equipment and time to measure Adjacent Channel Power Ratio (ACPR), which is crucial for determining the quality and categorization of integrated circuits, and do not efficiently allow for rapid testing across various signal types.
Innovation Solution
The implementation of Built-In-Self-Test (BIST) circuits within the transceiver, which include a two-tone source signal generator and an ACPR estimator, calculate ACPR values by extracting polynomial coefficients and applying weight factors to determine if the ACPR is within an acceptable range, allowing for self-testing without external equipment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If external testing equipment is used to measure ACPR, then measurement precision is improved, but device complexity and testing time increase
Solution Approach 1:
The transceiver circuit tests itself by using its own transmitter and receiver components. The receiver processes the transmitted signal and the baseband processor calculates ACPR using the received signal and stored reference signals, eliminating the need for external ACPR measurement equipment.
Solution Approach 2:
The baseband processor acts as an intermediary that receives the transmitted signal through the receiver, processes it using stored reference signals (W(t), Q(t)), and calculates ACPR values without requiring direct external measurement equipment.
2Measurement precision
If external testing equipment is used for ACPR measurement, then measurement accuracy is improved, but testing time is increased
Solution Approach 1:
Reference signals W(t) and Q(t) are pre-stored in memory for different modulation types. During testing, these pre-stored references are immediately used to calculate ACPR without requiring time-consuming external measurements or complex signal generation equipment.
Solution Approach 2:
The baseband processor continuously receives signals from the receiver and performs ACPR calculations in real-time using the received signal and stored references, enabling rapid sequential testing of multiple transceivers without equipment reconfiguration time.
3Measurement precision
If traditional ACPR measurement methods are used, then measurement accuracy is maintained, but adaptability to different signal types is reduced
Solution Approach 1:
The baseband processor is designed to handle multiple modulation types (QPSK, 16QAM, 64QAM, etc.) by selecting appropriate pre-stored reference signals from memory. The same hardware infrastructure supports diverse signal types, making the testing system universally applicable.
Solution Approach 2:
The system adapts to different signal types by changing the reference signal parameters (W(t), Q(t)) stored in memory corresponding to different modulation schemes. The baseband processor selects and uses the appropriate reference set based on the modulation type being tested, enabling accurate ACPR measurement across various signal formats.
Data Source
AI summary
An apparatus for testing a circuit includes a source signal input configured to receive a source signal, an evaluation signal input configured to receive an evaluation signal, and a coefficient extractor configured to extract a plurality of coefficients of a preselected polynomial representing the evaluation signal and the source signal. A weight factor storage contains a plurality of weight factors corresponding to frequency filters. An Adjacent Channel Power Ratio (ACPR) calculator is configured to calculate an ACPR value from the evaluation signal and the source signal by applying the plurality of weight factors from the weight factor storage to the plurality of coefficients the plurality of weight factors selected according to a main channel frequency range and an adjacent channel frequency range, and determining whether the ACPR value is within an acceptable range and generating a corresponding indication.