Digital Clock Frequency Modulation Without External Waveform Parts
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Solution Overview
Problem
Existing clock frequency modulators are complex and require external components to generate a low-frequency triangular waveform, which is necessary for modulating the oscillator frequency, making them unsuitable for complete integration.
Innovation Solution
A digital circuit comprising a frequency divider, counter, and digital-to-analog converter generates a triangular waveform from the oscillator's clock signal, allowing for internal modulation of the clock frequency without external components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a traditional frequency modulator circuit is used to generate a low-frequency triangular waveform, then the clock frequency can be modulated, but external components are required which prevent complete integration
Solution Approach 1:
The patent replaces the traditional analog triangular waveform generator (which requires external capacitors, resistors, and comparators) with a fully digital circuit implementation. The digital circuit uses a frequency divider, counter, and digital-to-analog converter to generate the modulation signal, eliminating the need for external passive components and enabling complete integration into the oscillator device.
Solution Approach 2:
The digital circuit performs multiple functions: it divides the clock frequency, counts pulses to generate a triangular waveform pattern, converts the digital waveform to analog, and applies it to modulate the oscillator frequency. This multi-functional digital block replaces what would traditionally require separate analog components, achieving both integration and functionality.
2Ease of manufacture
If external components are used to generate the triangular waveform, then the modulation function is achieved, but the cost and size increase
Solution Approach 1:
The patent merges the triangular waveform generation function with the existing digital logic of the oscillator device. By integrating the frequency divider, counter, and DAC into the existing device architecture, the patent eliminates the need for separate external components, thereby reducing both the quantity of components and the overall device size while maintaining the modulation functionality.
3Object-affected harmful factors
If a simple frequency modulation approach is used, then the circuit is simpler, but electromagnetic interferences are not effectively reduced
Solution Approach 1:
The patent implements periodic frequency modulation by generating a triangular waveform that continuously varies the oscillator frequency above and below its nominal value. This periodic variation distributes the harmonic energy across multiple sidebands, reducing the peak amplitude of individual harmonics and thereby effectively mitigating electromagnetic interference while using a relatively simple modulation circuit.
Data Source
AI summary
A clock frequency modulator for an oscillator having a digital circuit for the generation of a signal modulating the clock frequency, the digital circuit adapted to obtain, from the signal generated by the oscillator, a first pulse signal having a lower frequency than the clock frequency of the oscillator, a digital counter adapted to count the pulses of the first signal and to produce a digital signal and a digital-to-analog converter adapted to convert the digital signal in the signal for modulating the clock frequency of the oscillator.