FM Signal Processing in Wireless Receiver Antennas
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Solution Overview
Problem
Frequency modulated analog signals in wireless communication are not robust to propagation channel noise, which affects the reliability of signals in ISR and CAS missions.
Innovation Solution
A method for processing frequency modulated analog signals in a wireless communications receiver using multiple antennas and processing channels, where each channel samples the signal, estimates the signal-to-noise ratio, and combines estimates to produce a more robust demodulated signal, improving noise resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If frequency modulated analog signal is used for wireless communication, then interoperability and historical compatibility are improved, but robustness to propagation channel noise deteriorates
Solution Approach 1:
The patent combines signals from multiple diversity antennas (Q ≥ 2) through coherent processing to improve signal robustness. The method merges multiple received signals containing the same frequency-modulated analog information, using phase alignment and complex multiplication to combine them constructively, thereby overcoming the noise vulnerability of traditional FM while preserving compatibility
2Device complexity
If single antenna reception is used, then device complexity is reduced, but signal robustness and noise resistance deteriorate
Solution Approach 1:
The patent employs multiple diversity antennas (Q ≥ 2) that receive the same frequency-modulated analog signal through different propagation paths. The signals are combined coherently at the receiver by aligning phases and performing complex multiplication, which constructively adds the signal components while averaging out noise, thereby improving robustness without requiring complex adaptive modulation
3Device complexity
If simple frequency demodulation is used, then processing complexity is reduced, but output signal quality and noise resistance deteriorate
Solution Approach 1:
The patent performs preliminary phase alignment and complex multiplication of signals from multiple antennas before final demodulation. By pre-processing the received signals to align their phases and combine them constructively, the system prepares an enhanced input signal for the demodulator, improving output quality without adding complex adaptive modulation schemes
Data Source
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AI summary
The invention relates to a method for processing a frequency-modulated analog signal in a receiver (10) comprising Q receiving antennas (A1, ..., AQ) associated respectively with Q processing channels (CH1, ..., CHQ) each associated with a respective antenna, said method comprising, on each channel q, - i/ sampling the received signal and obtaining, by transposition of said sampled signal into baseband, complex samples mq(n); - ii/ obtaining a first estimate of the useful signal values ŝq(n) as a function of said complex samples mq(n); - iii/ estimating the signal-to-noise ratio RSB^q by calculating RSB^q=Sq2.Bq, with Sq = mod_moyq2 , Bq=1N⋅∑n=1Nmod_moyq−mqn2 and moy_moyq=1N⋅∑n=1Nmqn2, where N is a fixed integer; a second estimate ŝ(n) of the useful signal being determined as a function of the Q estimates of the signal-to-noise ratio RSB^q, q= 1 to Q and as a function of at least one of the said first estimates obtained ŝq(n) of the useful signal, q = 1 to Q.