DLL Phase Modulator Using Switched Phase Paths for Wideband Links
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Solution Overview
Problem
Phase locked loops (PLLs) are limited to narrowband applications and are not viable for wideband technologies, particularly in dense multipath environments, necessitating improved methods for phase modulation in modern telecommunication systems.
Innovation Solution
A wideband modulator employing a delay locked loop to generate phase shifted signals locked to a reference signal, with a multiplexer selecting one of these signals based on the angular component of the modulation symbol for polar modulation, enabling effective phase modulation in wideband communications.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a phase locked loop (PLL) is used for phase modulation, then phase modulation can be achieved, but the system is limited to narrowband applications and cannot support wideband technologies
Solution Approach 1:
The invention segments the phase modulation function into multiple discrete phase-shifted signal paths (e.g., 0°, 90°, 180°, 270° phases) generated by the delay locked loop. Instead of using a continuous PLL mechanism, the system divides the phase control into separate selectable paths, enabling wideband operation while maintaining phase coherence across multiple signal components
Solution Approach 2:
The invention changes the operating parameters by using a delay locked loop instead of a phase locked loop, fundamentally altering how phase control is achieved. The DLL generates phase-shifted signals through controlled time delays rather than frequency locking, enabling the system to operate effectively in wideband applications where PLLs fail
2Adaptability or versatility
If a delay locked loop with multiple phase shifted signals and a multiplexer is used, then wideband phase modulation is enabled, but the device complexity increases
Solution Approach 1:
The delay locked loop serves multiple functions simultaneously: it generates the carrier signal, creates multiple phase-shifted versions of the carrier, and provides coherent signaling across all phase paths. This multi-functionality reduces the need for separate signal generation circuits for each phase, thereby managing complexity while enabling wideband operation
Data Source
AI summary
An apparatus for phase modulation includes a delay locked loop configured to generate from a reference signal a plurality of phase shifted signals, each of the phase shifted signals being locked to the reference signal and having a different phase shift from the other phase shifted signals with respect to the reference signal, and a multiplexer configured to select one of the phase shifted signals.