Shared RF Cable Transmission with Delta-Sigma Noise Suppression
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Solution Overview
Problem
In wireless communication systems using delta-sigma modulation, transmitting an RF signal through a signal transmission path that carries a delta-sigma modulated signal is challenging due to superimposition of quantization noise, which affects signal quality and requires additional infrastructure, increasing system size.
Innovation Solution
A transmission system configuration where a first apparatus transmits a delta-sigma modulated signal and a second apparatus transmits an RF signal through the same signal transmission path, with the delta-sigma modulator suppressing quantization noise at specific frequency bands to prevent superimposition, allowing the RF signal to be transmitted without degrading signal quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If an RF signal is transmitted through a signal transmission path that carries a delta-sigma modulated signal, then the system size is reduced by eliminating additional transmission lines, but quantization noise superimposition degrades signal quality
Solution Approach 1:
The signal transmission path is segmented into different frequency bands: one band for delta-sigma modulated signals and another band for RF signals. The delta-sigma modulator suppresses quantization noise in the RF signal band, creating a clean frequency region where RF signals can be transmitted without interference from quantization noise.
Solution Approach 2:
The solution moves from time-domain signal transmission to frequency-domain signal transmission. By utilizing the frequency dimension, the system allows simultaneous transmission of delta-sigma modulated signals and RF signals through the same transmission path without interference, as they occupy different frequency bands.
2Adaptability or versatility
If quantization noise is suppressed at the frequency of the second signal, then the second signal can be transmitted through the same path, but this requires specific noise shaping in the delta-sigma modulation
Solution Approach 1:
The delta-sigma modulator's noise transfer function is modified to suppress quantization noise at specific frequency bands where RF signals need to be transmitted. By changing the noise shaping characteristics of the modulator, quantization noise is pushed to frequency regions that do not interfere with the RF signal transmission.
Data Source
AI summary
Provided is a transmission system including: a signal processing apparatus 2 configured to transmit, via a signal cable 4, a delta-sigma modulated signal obtained by performing delta-sigma modulation on a transmission signal that is an RF signal; and a wireless apparatus 3 configured to transmit, via the signal cable 4, a reception signal that is an RF signal. The signal processing apparatus 2 transmits the delta-sigma modulated signal to the wireless apparatus 3, and the wireless apparatus 3 transmits the reception signal to the signal processing apparatus 2. In the delta-sigma modulated signal, quantization noise is suppressed at the frequency of the reception signal. The reception signal is transmitted to the signal processing apparatus 2 while the delta-sigma modulated signal is being transmitted to the wireless apparatus 3.