Digital Transmit Spectral Shaping for UTP Cable EMC
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Solution Overview
Problem
Automotive vehicles face significant unwanted Radio Frequency (RF) emissions, particularly in the DAB and FM frequency ranges, due to the use of Unshielded Twisted Pair (UTP) cables, which can interfere with other electronic devices and roadside equipment, leading to reduced Electromagnetic Compatibility (EMC).
Innovation Solution
A transmitter device with a digital filter circuit and switching unit that selectively shapes the spectral power density of RF signals before transmission through UTP cables, allowing precise control of the spectral distribution to attenuate unwanted frequencies, thereby reducing electromagnetic pollution and enabling interference-free reception of DAB and FM signals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Weight of moving object
If Unshielded Twisted Pair (UTP) cables are used for transmitting RF signals, then cost and weight are reduced, but unwanted RF emissions increase causing electromagnetic interference
Solution Approach 1:
The patent applies preliminary action by implementing spectral shaping of the digital signal before transmission through the UTP cable. The filter circuit pre-processes the signal to attenuate frequency components that would cause unwanted RF emissions, thereby preventing electromagnetic interference before it occurs while maintaining the use of lightweight UTP cables
Solution Approach 2:
The patent changes the spectral parameters of the transmitted signal by applying frequency-dependent filtering. The filter circuit modifies the power spectral density of the digital signal, selectively attenuating certain frequency ranges to reduce RF emissions while preserving the integrity of the transmitted data signal
2Ease of manufacture
If Unshielded Twisted Pair (UTP) cables are used instead of Shielded Twisted Pair (STP) cables, then manufacturing cost is reduced, but electromagnetic compatibility deteriorates
Solution Approach 1:
The patent implements preliminary spectral shaping of the transmitted signal to pre-attenuate frequency components that would cause electromagnetic interference. This pre-processing allows the use of cost-effective UTP cables while maintaining electromagnetic compatibility through controlled spectral distribution
Solution Approach 2:
The patent modifies the spectral parameters of the transmitted signal using digital filtering techniques. By changing the power spectral density distribution and attenuating specific frequency ranges, the system achieves electromagnetic compatibility without requiring expensive shielded cables
3Object-generated harmful factors
If spectral shaping is applied to attenuate unwanted frequencies, then electromagnetic interference is reduced, but signal processing complexity increases
Solution Approach 1:
The patent replaces complex physical shielding mechanisms with digital signal processing techniques. Instead of using heavy shielded cables or complex filtering hardware, the invention uses digital filter circuits to achieve spectral shaping, reducing electromagnetic interference through software-controlled parameter adjustment
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
The solution provides effective spectral shaping of RF signals, reducing electromagnetic interference in critical frequency bands, allowing for reliable and interference-free reception of DAB and FM signals even with UTP cables, which are preferred for their cost and weight benefits over Shielded Twisted Pair (STP) cables.
Implementation Method 1
a filter circuit for (filtering and) spectrally shaping the generated digital transmit signal
Data Source
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AI summary
It is described a transmitter device (100) and a method for transmitting an analog signal (251, 261) via an electric cable (192). The transmitter device (100) comprises (a) a signal generation circuit (210) for generating a digital transmit signal (211) comprising a sequence of transmit symbols; (b) a filter circuit (230) for spectrally shaping the generated digital transmit signal (211, 221) and for outputting a filtered digital transmit signal (231); (c) a switching unit (240) comprising (c1) a first input terminal (242) for receiving the filtered digital transmit signal (231), (c2) a second input terminal (244) for receiving another digital transmit signal (297), (c3) an output terminal (246) for outputting a digital transmit output signal (241), wherein the digital transmit output signal (241) is based on, depending on a switching state of the switching unit (240), the filtered digital transmit signal (231) or the another digital transmit signal (297), and (c4) a control terminal (248) for receiving a control signal (285) from a control circuit (280), the control signal (285) being indicative for the switching state. The transmitter device (100) further comprises the control circuit (280); and a digital to analog converter (250) for receiving the digital transmit output signal (241) and for converting the received digital transmit output signal (241) to the analog signal (251, 261).