Transmit Power Calibration via Loopback Gain
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing methods for calibrating transmit power in communication systems, such as WLAN, require expensive and labor-intensive use of test equipment and sophisticated test environments, making them time-consuming and impractical for efficient power calibration.
Innovation Solution
The method involves determining the saturated output power of a power amplifier and using a loopback path to measure and calibrate the transmit power without external test equipment, by iteratively adjusting the power level based on loopback gain calculations, allowing for calibration within the communication device itself.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional test equipment is used for transmit power calibration, then measurement precision is improved, but device complexity and cost increase
Solution Approach 1:
The communication network device performs self-calibration by using its own receiver unit to measure the loopback signal from its transmitter unit. The device determines loopback gain and calculates transmit power calibration values autonomously without requiring external power meters or test equipment, making the system self-sufficient for calibration purposes
Solution Approach 2:
A loopback path is introduced as an intermediary component that couples the transmitter unit and receiver unit. This loopback path enables the transmit signal to be routed back to the receiver for measurement, serving as a mediator that facilitates the calibration process without requiring external test equipment
2Measurement precision
If external test equipment is used for calibration, then measurement precision is improved, but productivity decreases
Solution Approach 1:
The device performs autonomous self-calibration during normal operation or manufacturing without requiring external test equipment setup. The transmitter transmits a loopback signal and the receiver measures it, with the processor automatically calculating calibration values, enabling rapid calibration that significantly improves productivity compared to traditional external equipment methods
Solution Approach 2:
The calibration process skips the time-consuming steps of connecting external test equipment, setting up measurement environments, and manual data collection. The loopback method rushes through calibration by using internal components already present in the device, eliminating unnecessary steps and accelerating the calibration process
3Ease of manufacture
If loopback calibration method is used, then ease of manufacture is improved, but measurement precision may worsen
Solution Approach 1:
The patent replaces mechanical/physical test equipment (power meters, external measurement instruments) with electronic signal processing methods. The loopback gain is determined through electronic measurements and calculations using the device's own receiver and processor, substituting complex external measurement systems with simpler internal electronic operations that maintain adequate precision
Solution Approach 2:
The calibration process determines transmit power by calculating changes in signal parameters through the loopback path. By measuring the received power of the loopback signal and comparing it with the transmitted power, the system derives calibration values based on parameter relationships rather than absolute measurements, maintaining precision through relative measurement techniques
Data Source
AI summary
Functionality can be implemented to calibrate the output transmit power of a power amplifier of a network device without the use of test equipment. An RF signal can be transmitted at the saturated output power (of a power amplifier) from a transmitter unit to a receiver unit of the network device via a loopback path. A received power of the RF signal received via the loopback path can be measured. The loopback gain associated with the network device is determined based on the saturated output power and the measured received power. The output transmit power can be calibrated by iteratively decreasing the output transmit power by an unknown value, transmitting a new RF signal via the loopback path at the decreased output transmit power, measuring the new received power, and calculating the decreased output transmit power using the loopback gain and the measured new received power.