Digital Receiver Emulation for Band-Adjacent Signal Effects
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Solution Overview
Problem
Existing digital receiver emulation techniques struggle to accurately simulate the effects of signals that are adjacent or overlap with the receiver passband, particularly in dense signal environments, and lack efficient scalability for emulating multiple receivers.
Innovation Solution
The technique employs over-sampling and multiplexing of I-Q data streams to create a composite signal stream, applying band-limiting filters to match the digital receiver bandwidth, and decimating the signal to match the data rate, effectively emulating the effects of band-adjacent signals using Single-Sideband modulation and digital signal processing elements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional baseband-level digital signal processing is used to simulate receiver operation, then the simulation can be performed with simpler processing, but the ability to accurately simulate band-adjacent signals and their effects is lost
Solution Approach 1:
The signal processing is divided into distinct stages: over-sampling at a first rate, multiplexing to create composite streams, band-limiting filtering, and decimation to a second rate. This segmentation allows each stage to be optimized independently, achieving accurate band-adjacent signal emulation while managing computational complexity through structured processing steps.
Solution Approach 2:
The patent transitions from baseband-level processing to over-sampled processing at a higher rate, adding a temporal dimension to the signal representation. This enables the system to capture band-adjacent signal effects that would be lost in conventional baseband processing, while the subsequent decimation returns the signal to the required output rate.
2Reliability
If the receiver emulation includes accurate modeling of band-adjacent signal effects, then the simulation fidelity improves, but the computational resources and processing complexity increase
Solution Approach 1:
The system performs over-sampling and multiplexing of individual signal streams before combining them into a composite stream. This preliminary action at a higher rate enables accurate representation of band-adjacent effects, and the subsequent band-limiting filter and decimation steps efficiently reduce the computational load to match the required output rate.
Solution Approach 2:
The patent changes the sampling rate parameter dynamically, operating at an over-sampled first rate during signal generation and then transitioning to a lower second rate after decimation. This parameter change allows the system to achieve high simulation fidelity during processing while reducing computational complexity for output generation.
3Measurement precision
If the system processes signals at a higher over-sampled rate to capture band-adjacent effects, then the emulation accuracy improves, but the data processing rate and throughput decrease
Solution Approach 1:
The system employs periodic over-sampling during the signal generation phase to capture band-adjacent effects, followed by periodic decimation to reduce the data rate. This periodic action pattern allows the system to achieve high emulation accuracy when needed while maintaining efficient data processing rates through the alternating high-rate capture and low-rate output cycles.
Solution Approach 2:
The sampling rate parameter is changed from a high over-sampled rate during signal processing to a lower rate for output generation. This parameter change enables the system to achieve accurate emulation of band-adjacent signals during processing while improving overall data processing throughput for the final output.
4Adaptability or versatility
If the system emulates multiple digital receivers simultaneously, then the versatility and scalability improve, but the hardware resource requirements and system complexity increase
Solution Approach 1:
The patent creates a universal receiver emulation architecture where a single composite I-Q signal stream represents multiple receivers. By multiplexing individual receiver signals into a composite stream and applying band-limiting filters, the system can emulate multiple receivers simultaneously using the same hardware resources, thereby improving scalability and reducing per-receiver hardware requirements.
Solution Approach 2:
The system merges multiple receiver signal streams into a single composite I-Q data stream through multiplexing. This combining approach allows multiple receivers to be emulated simultaneously using shared hardware resources, reducing the overall hardware footprint while maintaining the ability to represent multiple receivers with different bandwidths and frequency characteristics.
Data Source
AI summary
A computerized simulation system includes a digital receiver emulator that applies over-sampling and multiplexing to in-phase and quadrature (I-Q) data streams to create a composite I-Q signal stream that represents a signal environment in a bandwidth wider than that of an assumed digital receiver bandwidth, applying a band-limiting filter to reduce the signal bandwidth so as to match the digital receiver bandwidth, and decimating the I-Q signal to match the data rate of the simulated digital receiver. The digital receiver can accurately emulate effects of band-adjacent signals that may be adjacent or overlap with the receiver passband, considering the characteristics of low-pass filters used in real-world receivers. The simulation system may be part of a training system that presents a simulated signal environment to a trainee.