ASK Modulator Circuit for Flexible Depth and Low Interference
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Solution Overview
Problem
Existing amplitude-shift keying (ASK) modulation technologies lack flexibility in modulation depth and suffer from inter-channel interference due to clock components in the output spectrum, and mixers like Gilbert mixers are non-linear, leading to inefficiencies.
Innovation Solution
An ASK modulator comprising a baseband unit that adds an additional value to amplitude values, a digital-to-analog converter to generate a differential signal, and a mixer to combine these signals, along with a Gilbert mixer design that uses operational amplifiers and active elements to achieve flexible modulation depths and reduce inter-channel interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multiple switches are used to distribute carrier wave power control for flexible modulation depths, then modulation depth flexibility is improved, but clock components are introduced in the output spectrum causing inter-channel interference
Solution Approach 1:
The patent extracts and removes the harmful clock components from the output spectrum through filtering techniques, while preserving the beneficial flexible modulation depth control achieved through multiple switches. The bandpass filter specifically targets and removes the clock frequency components that cause inter-channel interference.
Solution Approach 2:
The patent introduces a bandpass filter as an intermediary component between the multiple switches and the output. This filter mediates the signal path, allowing the flexible modulation control to function while blocking the harmful clock components from reaching the output spectrum.
2Object-generated harmful factors
If Gilbert mixers are used to avoid clock component issues, then inter-channel interference is reduced, but nonlinearity problems remain
Solution Approach 1:
The patent changes the operating parameters and configuration of the mixer circuitry to achieve both linearity and suppression of clock components. By adjusting the mixing architecture and operating conditions, the system achieves improved linearity while maintaining the ability to filter clock components effectively.
3Device complexity
If on-off keying is used with a single switch for simple configuration, then device complexity is reduced, but modulation depth flexibility is lost
Solution Approach 1:
The patent segments the carrier wave power control function into multiple switches instead of using a single switch. This segmentation allows independent control of different power levels, enabling flexible modulation depths while maintaining a relatively simple overall configuration that builds upon the basic on-off keying concept.
Data Source
AI summary
An ASK modulator includes a baseband unit which obtains a sequence comprising at least one amplitude value and adds an additional value to each of the at least one amplitude value to generate a modified sequence; a digital-to-analog converter coupled to the baseband unit, the digital-to-analog converter converts the modified sequence to generate a first signal, the additional value is determined based on a half scale of the digital-analog converter; and a mixer which receives the first signal and a second signal and generate a modulated signal by mixing the first signal with the second signal.