Phase Noise Improvement in Fractional-N Synthesizer with 90" Phase Shift Lock
نویسندگان
چکیده
An effective technique for phase noise improvement in a fractional-N synthesizer is described. The method requires using in a 90" phase shift lock a non-linear continuous-time or sampled-data block before the loop filter. Behavioral simulations on a fractional-N synthesizer incorporating different non-linear blocks and a second-order single bit sigma delta modulator show that it is possible to achieve phase noise improvements at medium frequency as good as 17 dB.
منابع مشابه
A sub-0.75°RMS-phase-error differentially-tuned fractional-N synthesizer with on-chip LDO regulator and analog-enhanced AFC technique
This paper presents a low-phase-error wideband fractional-N frequency synthesizer. Differential tuning is described and a level shift circuit is proposed to obtain symmetrical tuning range. On-chip LDO regulator is designed to improve the power supply rejection for VCO. A voltage monitor is used to enhance the digital AFC technique to overcome the temperature variation. The synthesizer was impl...
متن کاملA Fractional-N Frequency Synthesizer Architecture Utilizing a Mismatch Compensated PFD/DAC Structure for Reduced Quantization-Induced Phase Noise
Techniques are proposed to dramatically reduce the impact of quantization noise in fractional-N synthesizers, thereby improving the existing tradeoff between phase noise and bandwidth that exists in these systems. The key innovation is the introduction of new techniques to overcome nonidealities in a phase-frequency detector (PFD)/digital-to-analog converter (DAC) structure, which combines the ...
متن کاملDual Phase Detector Based Delay Locked Loop for High Speed Applications
In this paper a new architecture for delay locked loops will be presented. One of problems in phase-frequency detectors (PFD) is static phase offset or reset path delay. The proposed structure decreases the jitter resulted from PFD by switching two PFDs. In this new architecture, a conventional PFD is used before locking of DLL to decrease the amount of phase difference between input and outpu...
متن کاملA ∆Σ Fractional-N Frequency Synthesizer with Multi-Band PMOS VCOs for 2.4 and 5GHz WLAN Applications
This paper presents a fully integrated multi-band frequency-synthesizer architecture. The synthesizer is a ∆Σ based fractional-N frequency synthesizer with three on-chip LC tuned VCOs to cover the entire frequency bands specified in IEEE802.11b, and 802.11a WLAN standards. The synthesizer includes a ∆Σ noise shaper, a dead-zone-free phase frequency detector and a fully differential charge pump....
متن کاملA-New-Closed-form-Mathematical-Approach-to-Achieve Minimum Phase Noise in Frequency Synthesizers
The aim of this paper is to minimize output phase noise for the pure signal synthesis in the frequency synthesizers. For this purpose, first, an exact mathematical model of phase locked loop (PLL) based frequency synthesizer is described and analyzed. Then, an exact closed-form formula in terms of synthesizer bandwidth and total output phase noise is extracted. Based on this formula, the phase ...
متن کامل