AND JEFFREY L. CUTCHER Motorola Inc. Plantation, FL Fractional-N synthesizers are highly desirable in communication systems because of their high frequency resolution output. This resolution is made possible by dithering the divide value using the output of a sigma-delta modulator. A typical sigma-delta fractional-N frequency synthesizer is shown in Figure 1. The tri-state phase frequency detec...

A new approach to frequency synthesis permits the achievement of excellent spectral purity, high agility, very fine resolution, low power consumption and low cost. The principle of the proposed Phase Digital Synthesizer (PDS) is that the control signal of the PLL is formed by a multi frequency-phase comparator with phase splitting of the reference and VCO signals into a large group of signals w...

This paper investigates the design and performance of the PLL (Phase Locked Loop). The proposed PLL designed with PFD (Phase Frequency Detector), CP (Charge Pump), first order Low Pass Filter and CS-VCO (Current Starved-Voltage Control Oscillator), in this paper the designed PFD used for proposed PLL is free from dead zone. The VCO used for the designed PLL shows larger tuning range and high ga...

In this paper we introduce and describe an optimized phase detector suited to 16-QAM receivers which prevents ambiguous locking and performs relatively rapid acquisition. Based on a new decision scheme, the proposed phase detector outperforms a classical decision directed phase detector over a Gaussian channel. An analytical analysis of the proposed phase detector variance is carried out and va...

A two-axis optical imaging system using a Lissajous scan pattern with non-integer frequency ratio is presented. A waveguide with precisely tuned mechanical resonant frequencies is constructed by dip coating two fibres with a transparent polymer. Motion is achieved by mounting a waveguide cantilever at 45° on a single piezoelectric actuator with a dual-frequency drive. Confocal signal collection...

The remarkable precision of frequency-comb (FC) lasers is transferred to the extreme ultraviolet (XUV, wavelengths shorter than 100 nm), a frequency region previously not accessible to these devices. A frequency comb at XUV wavelengths near 51 nm is generated by amplification and coherent up-conversion of a pair of pulses originating from a near-infrared femtosecond FC laser. The phase coherenc...

Two modified methods for assaying sodium diclofenac were developed by GC and HPLC. Diclofenac was converted into methyl ester derivative by methyl iodide in acetone. The ester was extract and subjected to GLC with flame ionization detector. %5 SE-30/chrom W-HP (80-100 mesh) was used as a column in GC. For reversed phase HPLC, the mobile phase was methanol and water (55-45). The separation was p...

One method to enable fast acquisition of a phase-locked loop (PLL) in spite of large frequency offsets and small PLL bandwidths is to use an additional AFC loop. A suitable frequency error detector (FED) for large frequency offsets is the well-known balanced quadricorrelator. This FED is shown to produce great pattern jitter if it is to work with digital modulated MQAM and MPSK signals (M > 2) ...

Introduction In recent years, personal communications in high Megahertz and low Gigahertz frequency ranges are booming. Behind this achievements was the technological progress in integrated circuitry on one hand and application of frequency synthesis on the other hand. The task of the phase locked loops is to maintain coherence between input (reference) signal frequency, f i , and the respectiv...

Multiplying delay-locked loops (MDLLs) are gaining popularity due to their superior noise performance over conventional phase-locked loops (PLLs) [1,2]. Recent designs are trending towards an all-digital implementation that provides advantages such as compact area, good scalability and low power compared to traditional analog implementations. Achieving fractional frequency multiplication is, ho...