DDS Signal Generator Architecture Without Down-Conversion
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Solution Overview
Problem
Current signal generators require complex and costly down-conversion methods to achieve a wide frequency range, leading to high circuit complexity, component count, and power consumption.
Innovation Solution
The output signal of the DDS signal source is directly connected to the level adjustment device or output, eliminating the need for a down-converter and reducing circuit complexity, allowing for a more compact design with lower power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a down-converter is used to generate the lower frequency range, then the frequency range can be extended, but the circuit complexity and manufacturing costs increase significantly
Solution Approach 1:
The patent extracts and eliminates the down-converter component from the signal generator architecture. By using a DDS signal source that can directly generate low-frequency signals without requiring frequency conversion, the complex down-conversion stage (including mixers, local oscillators, and associated control circuits) is removed entirely, thereby reducing circuit complexity while maintaining the ability to cover the required frequency range
Solution Approach 2:
The DDS signal source is designed to perform multiple functions: it can directly generate both high and low frequency signals within the required range, eliminating the need for separate frequency conversion paths. This multi-functional approach allows a single component to replace what would traditionally require multiple specialized components (VCO, mixer, low-pass filter, and down-converter), thereby simplifying the overall circuit architecture
2Adaptability or versatility
If frequency division is used to generate lower frequencies, then the frequency range can be extended, but the number of filters and circuit stages increases
Solution Approach 1:
The patent removes the multi-stage frequency division architecture and associated low-pass filters by implementing a DDS-based direct generation approach. The DDS signal source inherently produces the required frequency outputs without needing external frequency division stages, thereby eliminating the cascade of dividers and filters that would otherwise be necessary to generate low-frequency signals from a high-frequency VCO output
Solution Approach 2:
The patent replaces the mechanical/electrical frequency division system (with its multiple discrete circuit stages) with a digital signal generation approach. The DDS architecture uses digital logic and timing circuits to directly synthesize the required frequencies, substituting a complex multi-stage analog frequency division system with a more integrated digital solution that achieves the same frequency range extension with fewer components
3Adaptability or versatility
If a down-converter with high-frequency oscillator is used, then the lower frequency range can be generated, but power consumption increases
Solution Approach 1:
The patent extracts and removes the high-frequency oscillator and down-converter subsystem that would be required to generate low-frequency signals through frequency conversion. By using a DDS signal source that can directly generate low-frequency outputs, the system eliminates the power-hungry high-frequency oscillator and mixing circuits, thereby significantly reducing overall power consumption while maintaining the ability to cover the required frequency range
Data Source
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AI summary
The invention concerns a signal generator (20) having a DDS signal source (21), which operates according to the principle of direct digital synthesis (DDS), and having a PLL signal synthesizer (24, 25, 26, 27), which operates according to the principle of the closed phase locked loop (PLL), while using the signal of the signal source (21) as a reference signal. In order to generate a portion of the entire frequency range of the output signal of the signal generator (20), the DDS signal source (21), without additional frequency division or mixing, can be directly connected to the output (34) or to a level setting device (33) of the signal generator (20) via a direct connection (32).