RF Signal Loopback in Outdoor Units via Amplifier Gain Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing radio frequency signal loopback methods in split digital microwave systems suffer from limited transmitter-receiver isolation and frequency-dependent power leakage, restricting loopback functionality to only certain frequencies and service modes.
Innovation Solution
The implementation of a radio frequency signal loopback method using an outdoor unit with a splitter module to split signals into two branches, an amplifier to enhance signal power, and a duplexer to filter and combine signals, allowing for loopback at any frequency and service mode, with power control to adjust amplifier gain according to service mode requirements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the duplexer is used to directly leak the transmission signal for loopback, then the loopback function is implemented, but the leaked signal has small power due to transmitter-receiver isolation and frequency response characteristics
Solution Approach 1:
An amplifier is introduced as an intermediary component between the duplexer and the receiving module. The amplifier receives the weak leaked signal from the duplexer, amplifies it to the required power level, and then outputs it to the receiving module. This mediator component resolves the power deficiency caused by the duplexer's isolation characteristics while maintaining the loopback function.
Solution Approach 2:
The system uses its own transmitted signal for loopback testing by leaking it through the duplexer and amplifying it back to the receiving module. This self-service approach allows the ODU to perform self-diagnosis and testing without requiring external test equipment, utilizing the existing transmission signal itself for the loopback function.
2Adaptability or versatility
If the receiving filter leaks transmission signals with different frequencies, then loopback is achieved, but the leaked signals have different powers due to frequency response characteristics
Solution Approach 1:
The control module monitors the service mode and frequency information, then provides feedback control to the amplifier to adjust its gain dynamically. This feedback mechanism ensures that regardless of the frequency response characteristics of the receiving filter, the amplifier compensates by adjusting its amplification factor, thereby maintaining consistent output power for loopback signals across different frequencies and service modes.
3Ease of operation
If signal leakage through the duplexer is used for loopback, then loopback function is provided, but loopback is only achievable at part of frequencies and service modes
Solution Approach 1:
The system transitions from a static loopback approach (fixed gain amplifier) to a dynamic one where the amplifier gain is continuously adjusted based on the current service mode and frequency. The control module dynamically controls the amplifier's power supply current according to the service mode, enabling the system to adapt to different frequencies and service modes while maintaining consistent loopback functionality.
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 effective loopback of signals at any frequency in the working frequency band and any service mode, ensuring consistent and adjustable power levels for reliable communication.
Implementation Method 1
an amplifier to enhance signal power
Implementation Method 2
a duplexer to filter and combine signals
Implementation Method 3
a combining module to combine the signal output by the amplifier with the signal output by the duplexer
Data Source
Figure 1~2
Figure 3
Figure 4
AI summary
Embodiments of the present invention provide a radio frequency signal loopback method and an outdoor unit. The outdoor unit includes: a transmitting module, a receiving module, a splitter module, a combining module, a duplexer, and an amplifier. The transmitting module is configured to transmit a signal; the splitter module is configured to split the signal transmitted by the transmitting module into two branches, where one branch of the signal is input into the amplifier, and the other branch of the signal is input into the duplexer; the amplifier is configured to amplify the signal from the splitter module; the duplexer is configured to filter the signal from the splitter module and then output the signal to an antenna, and filter an external signal received by the antenna and then output the external signal to the combining module; the combining module is configured to combine the signal output by the amplifier with the signal output by the duplexer, and then output a combined signal to the receiving module; and the receiving module is configured to receive the combined signal output by the combining module. By using the technical solutions provided in the present invention, loopback of a signal at any frequency in a working frequency band and any service mode of the outdoor unit can be implemented.