Radar transmitter module for digital modulation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional digitally modulated radar systems face challenges in reducing the power of side lobes in the frequency domain, which is undesirable in regulatory environments such as 77 GHz automotive radar, due to the modulation of carrier signals with digital signals.
Innovation Solution
A digitally modulated radar transmitter module that combines a repeating digital sequence signal with one or more phase-delayed copies of itself to modulate a high-frequency carrier signal, altering the positioning and power of side lobes, thereby reducing the power in individual side lobes. This can be achieved by using phase-delay circuits to generate phase-shifted copies of the digital sequence or clock signal, which are then combined to create a modulated signal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of information
If a carrier signal is modulated with a digital signal in digitally modulated radar, then the identification code capability and time-of-flight measurement capability are improved, but side lobes with significant power are generated in the frequency domain
Solution Approach 1:
The digital sequence signal is segmented into multiple phase-delayed copies that are combined through mixing. This segmentation approach redistributes the spectral energy, reducing the power in individual side lobes while maintaining the overall identification code capability of the modulated signal.
Solution Approach 2:
Phase delays are applied asymmetrically to different copies of the digital sequence signal. By using irregular phase spacing rather than uniform spacing, the spectral distribution is optimized to minimize side lobe power while preserving the main signal's identification characteristics.
2Object-generated harmful factors
If phase-delayed copies of the digital sequence signal are combined to reduce side lobe power, then side lobe power is reduced, but the device complexity increases
Solution Approach 1:
The phase-delay circuits and mixer are designed to serve multiple functions: they reduce side lobe power while simultaneously maintaining the identification code capability and time-of-flight measurement capability. This multi-functionality approach reduces the need for separate components, thereby limiting the increase in device complexity.
Solution Approach 2:
The system adjusts phase delay parameters and mixing coefficients to optimize side lobe suppression. By tuning these parameters, the system achieves effective side lobe power reduction without requiring complex additional hardware, as the same circuits can be configured for different optimization goals.
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 effectively reduces the power in side lobes, improving compliance with regulatory power masks and minimizing adjacent channel interference, while maintaining the identification capabilities of the digital signal.
Implementation Method 1
a mixer configured to combine the digital sequence signal with at least one phase-delayed copy of the digital sequence signal, to provide a combined signal
Implementation Method 2
a modulator configured to modulate a relatively high-frequency carrier signal, in dependence on the combined signal, to provide a modulated signal
Implementation Method 3
the modulator is an amplitude modulator and the modulated signal is an amplitude modulated signal, or the modulator is a frequency modulator, and the modulated signal is a frequency modulated signal
Data Source
Figure 1~2
Figure 3a
Figure 3b
AI summary
A digitally modulated radar, DMR, transmitter module (600) is disclosed comprising: a sequence generator (610,612,614,616), configured to generate a repeating digital sequence signal based on a relatively low-frequency clock signal; a mixer (630) configured to combine the digital sequence signal with at least one phase-delayed copy of the digital sequence signal, to provide a combined signal; and a modulator configured to modulate a relatively high-frequency carrier signal, in dependence on the combined signal, to provide a modulated signal. Corresponding systems and methods are also disclosed.