Low Distortion Quick Response Noise Filter Realized withAverage Peaks Method

The filter proposed in this paper is expected to reduce noise whose frequency is lower than higher order harmonics of real signals.It is based on the distributive characteristics of noise,and uses analog circuits to select the high peak and low peak of the input signal and applies their average in order to reduce random noise.So it has no cutoff frequency and higher order harmonics of real signals are remained.As a result,it gives an instant response to changes in input signals and retains the integrity of real signals.Furthermore,it has only a small phase delay.The simulation results of slew rate,phase delay and spectral analysis under MULTISIM indicate that the quick response noise filter achieves a high slew rate of 472 V/ms and the phase shift is nearly zero.By having it used in a color tester design,it is also demonstrated that the proposed filter effectively reduces noise and remains signal integrity.With the filter 's help,the relative standard deviation of the spectrograph decreases from 1% to 0.22%,indicating better stability.

A low power and low distortion rail-to-rail input/output amplifier using constant current technique

A rail-to-rail amplifier with constant transconductance,intended for audio processing,is presented.The constant transconductance is obtained by a constant current technique based on the input differential pairs operating in the weak inversion region.MOSFETs working in the weak inversion region have the advantages of low power and low distortion.The proposed rail-to-rail amplifier,fabricated in a standard 0.35μm CMOS process,occupies a core die area of 75×183μm2.Measured results show that the maximum power consumption is 85.37μW with a supply voltage of 3.3 V and the total harmonic distortion level is 1.2%at 2 kHz.

Low Distortion 1.31μm AlGaInAs/InP MQW DFB Laser Module for CATV Systems

A high power and low distortion 1.31 μm AlGaInAs/InP multiquantum well distributed feedback laser diode (MQW DFB LD) with RWG structure has been developed by MOCVD technique. The fiber output power of butterfly packaged module with optic isolator P f is more than 10 mW, threshold current is in the range of (13～20) mA, slope efficiency, E s>0.30 W/A and side mode suppression ratio, R S,M,S >35 dB. The composite second order, O C,S <-61 dBc and composite triple beat, B C,T <-65 dBc are obtained by test frequencies of (45～550) MHz with 60 PAL channels. In the test conditions the carrier to noise ratio, R C,N >51 dB.

Low/distortion on Exterior Surface of Auto Body and Its Correction Method

Surface low/distortion is one of the most challenging surface deflections that have a great effect on the exterior appearance of automobiles.Most studies on surface distortion/deflection have focused on evaluation and visualization techniques,the research work on correction or prevention of surface low/distortion is limited,and there is no perfect surface low/distortion corrective method that can satisfy the needs of the engineering.A B-spline based geometry morphing algorithm is proposed and then a new program based on UG-NX platform is developed to modify the die face in the surface low/distortion areas.To verify this developed system,the experimental dies that can replicate the surface low/distortion phenomenon successfully is put to use.Five geometric variables are introduced to describe the basic geometry of typical depression features of automotive outer panels.The experimental dies are then designed to reflect various combinations of these geometric parameters.The stamping experiments are conducted on cold rolled grade 5（CR5） sheet steel and various static measurements,such as oil-stoning,laser scanner,etc,are performed to measure and record the surface low/distortions.Three approaches including good bearing,holds in blank and die face morphing that aim to correct low/distortions are tried out and surface low/distortions are observed in the specimen with reverse draw depth of 10 mm.The measurement results show that die morphing is a practical and effective method to correct the surface low/distortion.The correction method proposed can be used to minimize the occurrence of surface low/distortion in die manufacturing,which has certain reference significance to the correction of surface low/distortion.

Low stress no distortion welding for aerospace shell structures

To fit in with the strict geometrical integrity and ensure dimensionally consistent fabrication of the welded aerospace structures. the low stress no distortion(LSND)welding, a technique for thin materials, was poineered and developed to provide an ininprocess active control of welding distortion. Satisfactory distortion free results were achieved in both welding of jet engine cases of heat-resistance alloys and rocket fuel tanks of aluminuim alloys, and there need no. reworking operations for post-weld distortion correction. Based on the 'static' method a newly developed method for dvnamic in-process control is also discussed in this paper. Both methods provide quanutiative in-process control of incompatible strains in weld zone and low stress no distortion welding results.

Effects of distance between arc and heat sink on stress and distortion in DC-LSND welding technology

The characteristics of temperatures, stresses and strains fields have been studied numerically for a titanium alloy sheet welded with an improved gas tungsten arc welding method, in which a trailing spot heat sink is introduced to control the welding stress and distortion. The impinging jet model is employed to describe the internee heat transfer between the cooling media and the top suufuce of the workpiece. The influcnee of the distance between arc and heat sink is investigated. Results show that there is an ideal range of distance. Using the ideal distance, a low stress and no distortion welding structure can be derived.

Improved low-distortion sigma-delta ADC with DWA for WLAN standards

An improved low distortion sigma-delta ADC（analog-to-digital converter） for wireless local area network standards is presented.A feed-forward MASH 2-2 multi-bit cascaded sigma-delta ADC is adopted; however,this work shows a much better performance than the ADCs which have been presented to date by adding a feedback factor in the second stage to improve the performance of the in-band SNDR（signal to noise and distortion ratio）,using 4-bit ADCs in both stages to minimize the quantization noise.Data weighted averaging technology is therefore used to decrease the mismatch noise induced by the 4-bit DACs,which improves the SFDR（spurious free dynamic range） of the ADC. The modulator has been implemented by a 0.18μm CMOS process and operates at a single 1.8 V supply voltage. Experimental results show that for a 1.25 MHz @-6 dBFS input signal at 160 MHz sampling frequency,the improved ADC with all non-idealities considered achieves a peak SNDR of 80.9 dB and an SFDR of 87 dB,and the effective number of bits is 13.15 bits.