Pdf optimized quantizer circuit

A chargebased cmos parallel analog vector quantizer. In case of singlebit or lowresolution internal quantizer, comparators integrated with passive type adder by using additional capacitors are typically used. For a singlebit modulator, the requirement for the quantizer is relaxed because imperfections in this stage. The slope for several n 0 values are listed in the table. A new high efficiency rf switchmode power amplifier. The vco quantizer is followed by a 1 st order digital integrator with gain k i. For schematic, bill of materials and theory of operation for newer boards, download this pdf file. Rather than allocate a uniform step size, as would be optimum for a uniform pdf, the lloyd max approach identifies decision boundaries according to the mean values of equal area partitions of the pdf cur. Deltasigma or sigmadelta, modulation is a method for encoding analog signals into digital signals as found in an analogtodigital converter adc.

Quantization, in mathematics and digital signal processing, is the process of mapping input values from a large set often a continuous set to output values in a countable smaller set, often with a finite number of elements. Adaptive quantization using piecewise companding and. The maximally decimated mband filter bank with the bank of pdfoptimized. This allows further room for more efficient circuit design. A power dissipation and area tradeoff can be achieved where the modulator order, the quantizer resolution and the sampling frequency are optimized resulting in a 3rd order 4bit modulator. Improved fault tolerance of turbo decoding based on optimized. Sigmadelta modulator design and analysis for audio application. These algorithms require at least 8 cnot gates for n 2, while three cnot gates are necessary and suf. For example, it is preferable to avoid the expense of doublepoly capacitors, thickoxide transistors for 5v operation, or other analog process enhancements when analog circuits such as data. The set of inputs and outputs of a quantizer can be scalars scalar quantizer. Topologies are optimized for minimizing the complexity of the topologies, maximizing the sharing of circuitry for different modes, maximizing the topology robustness with respect to circuit nonidealities, and minimizing total power consumption.

Deltasigma data conversion in wireless transceivers 303 fig. Encode each input value by associating it with index value of quantization region. Otherwise, there would be a strong possibility of having some missing codes due to process parameter variations. The use of vcobased quantization within continuoustime ct analogtodigital converter adc structures is explored, with a custom prototype in 0. Wooley, the design of sigmadelta modulation ad converters. An optimized circuit for processing of emg signals has been designed and presented in this paper. Transistor sizes in the quantizer and the dwa are optimized to satisfy critical timing requirements. Optimized product quantization tiezheng ge, kaiming he, qifa ke, and jian sun abstractproduct quantization pq is an effective vector quantization method. Wang, lab manual for multimedia lab, experiment on. Hence, the power supply voltage for the dac, counter and analog buffer circuit needed to be increased to 5v. The architecture and circuit design are optimized for scalable lowpower fullyautonomous computing applications. For each input value with a magnitude less than, the quantizer generates the corresponding output sample by rounding the input value to the nearest multiple of.

Simulated results are presented for a 2 ghz 25 w gan power device. Assuming that you know the pdf of the samples to be quantized design the quantizers step so that it is optimal for that pdf. For uniform pdf x max x f x x 12x max want to uniformly quantize an rv x ux max,x max assume that desire m rls for r. The lowdistortion feedforward architecture, though, generally requires an analog adder in front of the quantizer. A smooth input signal can take on a stairstep shape after quantization. The folding factor, f f, is the number of segments that the input is folded into. Nonuniform quantization pdf optimized quantization problem. Analysis of sample and hold circuits for analog to digital converters the folding operation reduces the total number of comparators needed to determine the digital signal. The source abstractly models for example an awgn communication channel, with a certain gain r and a noise variance.

Improved fault tolerance of turbo decoding 189 figure 1. Rounding and truncation are typical examples of quantization processes. A dualveobased quantizer with highly improved linearity and. Input offset sampling is used to minimize the effects of errors in the quantizer thresholds that are generated by a resistor string. The simplest quantizer converts an analog input voltage to a 1bit. Thus pdfoptimized vq can prevent the codebook from overfitting to the training data, and. Figure 3 g shows the analog input signal and output signal of second order sdm.

For a sigmadelta encoded pulse train, the power ef. Chapter 6 adaptive quantization without side information1. Supposition density of quantization noise as default of optimization result without need to additional circuit or filter, the. Electrical and computer engineering presented on september 15. Each quantizer is represented by its equivalent noise model, and the analysis and synthesis banks by the equivalent polyphase structures. The tunable delay circuit in the quantizer is designed to adjust the. Rather than allocate a uniform step size, as would be optimum for a uniform pdf, the lloyd max approach identifies decision boundaries according to the mean values of equal area partitions of the pdf curve. The 2bit quantizer and 2bit dacs have 6db snr improvement and better stability over the single bit quantizer and dacs. In the case of uniform quantizers, the pdf of the analog sample was assumed to beuniform, and therefore, we obtained the closed form solutions for optimal decision regions and output levels. The performance results show that the architecture achieves low power, high speed and less area.

The block uses a roundtonearest method to map signal values to quantized values at the output that are defined by the quantization interval. It is also used to convert high bitcount, lowfrequency digital signals into lower bitcount, higherfrequency digital signals as part of the process to convert digital signals into analog as part of a digitaltoanalog converter dac. Besides, due to the dualvco structure, the dynamic range of. Implemented in a 3rdorder single loop architecture with 5level quantizer 90nm cmos 74db sndrpeak, 600khz bandwidth 6. The direct conversion approach is a good one for exploiting todays adc. The idea that an adc can be put at the antenna and somehow rid a high performance radio of the lna, bpf, agc, and mixer is a pipe dream. The optimal is around 2 here since the sqnr increases very slowly when is larger than 2. The user writeable quantizer also has a softness control which can allow the unquantized voltage to slowly shift into the quantized voltage, or act as a simple slew between quantized voltages. Use the simulink to draw the characteristic of a quantizer having the following io relation.

The goal of optimum quantization is to adjust the quantization scheme to reconstruct the set of. A new optimization of noise transfer function of sigmadelta. Improved fault tolerance of turbo decoding based on. Ee368b image and video compression quantization no. Assuming that you know the pdf of the samples to be quantized design the quantizers step so that it is. Architecture and algorithm the architecture of the clustering circuit is shown in fig. The operating margins are optimized by adjusting the amplitude of the accoupled highspeed digital code signal. Deltasigma data conversion in wireless transceivers. February 2000 circuits, systems and computers, 1977. I need a 1 bit quantizer since my modulator is one bit. Q171 quantizer bank analog modular synthesizers for. The signal processing is implemented in current mode to allow efficient arithmetic operations and wide linear range. A chargebased cmos parallel analog vector quantizer gert cauwenberghs johns hopkins university ece department 3400 n.

Telecommunications circuits laboratory, epf lausanne, 1015 lausanne, switzerland. Temes deltasigma analogtodigital converters adcs are widely used in wireless transceivers. K vco is the vco voltage to frequency gain and m is the number of vco phases. Circuit design details and measurement results for a 15 bit audio modulator are given. Quantize and encode floatingpoint input into integer output. Moreover, a passive adder is introduced in this paper, instead normal active adder. It features a thirdorder activerc loop filter, a very lowpower 4bit flash quantizer, and an efficient excessdelay compensation scheme to reduce power dissipation. For uniform pdfx max x f x x 12x max want to uniformly quantize an rv x ux max,x max assume that desire m rls for r.

The frequencytocount gain of the linear quantizer is proportional to the nominal count n 0 while that of the bf quantizer is proportional to n 01 2. Using relay as a comparator1 bit quantizer in simulink. The whole comparator is a purely dynamic circuit controlled by clocks, which is very power ef. A product quantizer can generate an exponentially large codebook at very low memorytime cost. Circuit design an 11bit low power sigmadelta modulator for digital audio application is given, using a single bit quantizer. Nonidealities associated with 2nd integrator and quantizer when referred to the sdinput is attenuated by 1st integrator high gain the only building block requiring lownoise and high accuracy is the 1st integrator ref. Quantization, in mathematics and digital signal processing, is the process of mapping input. The singlebit quantizer is realized using a regenerative comparator and an sr latch, shown in fig. Pdf constantoptimized quantum circuits for modular. The quantizer block discretizes the input signal using a quantization algorithm. The default jumpers are set for the quantizer to accept a unipolar voltage range of 010 volts. The delayed output is fed to a divider 34 and another circuit 38,39,40 determines for each sequence the maximum value of the ratio between each of.

Optimized switchedcapacitor sigmadelta ia analogdigital converter adc for wireless transceiver xuepirrg. Instead of devoting attention to the signal being quantized, we shall consider its probability density function. Pdf optimized parametric vector quantization of speech line. The maximally decimated mband filter bank with the bank of pdfoptimized quantizers and a bank of scalar compensators dotted lines are shown in fig. For a signal x with given pdf find a quantizer with m representative levels such that fx x solution. The essence of pq is to decompose the highdimensional vector space into the. Cascade of integrators with feedforward ciff scheme, combined with the optimized gain coefficients, was adopted to avoid of the integrators. Hi i am trying to model a sigmadelta modulator in matlabsimulink. The penalty is that the linearity of the feedback dacs should be considered carefully so that the nonlinearity doesnt deteriorate the adc performance. Instead of using subtractors, 3bit adders are used to simplify the circuitry. Analogtodigital converters for software definable radios. Figure 3 d shows the circuit layout of fifth order sdm in simulink. Figure 1 shows the block diagram of the simplified qvns bias technique, where two josephson arrays in the quantizer are driven by two highspeed bias leads, data d and datacomplement d.

A multiphase vco quantizer based adaptive digital ldo in. Consider a symmetric scalar quantizer with 3 intervals, qx 8 a and a quantizer input with a zeromean laplace pdf, fx 1 2m e jxj m a derive the optimal reconstruction value bas a function of the decision threshold afor mse distortion. Channeloptimized vector quantization with mutual information as. For mixedsignal ics with high digital circuit content, singlepoly cmos optimized for digital circuits can provide the lowest overall implementation cost. The maximally decimated mband filter bank with the bank of pdf optimized quantizers and a bank of scalar compensators dotted lines are shown in fig. Design of a 3 sigmadelta modulator optimized for class.

Abstract of ep0675653 the circuit includes a delay circuit for a received sequence of words. Quantization information theory, ieee transactions on. Existing algorithms for nqubit circuit synthesis remain a factor of four away from lower bounds and fare poorly for small n. A wideband lowpower continuoustime deltasigma modulator for next generation wireless applications. The result of the 3bit adders without the overflow is similar to the output of the subtractors. The paper presents a case study for designing topologies for a three mode recon. This circuit acquires emg signals from surface of the skin using bipolar electrodes and enables. This works best for the majority of quantizer uses dealing with pitch voltages. Feedforward modulator architecture has gained popularity recently because of the small voltages wings in the loop filter of the modulator. A 12bit, 10mhz bandwidth, continuoustime adc with a. Ee398a image and video compression quantization no. Convex optimization of a firstorder sigma delta modulator. Electrical and computer engineering presented on september. Lloydmax quantizer lloyd,1957 max,1960 m1 decision thresholds exactly halfway between representative levels.

Download citation pdf optimized parametric vector quantization of speech line spectral. Zeros and poles of sigmadeltas loop filter is optimized and located by genetic algorithm with assumption loop filter stability and final quantization noise density of modulator will be significantly decrease. Therefore, the optimal should be chosen to maximize the sqnr and meanwhile, to minimize the decrease of the ol. This results in a nonuniformquantizer and is referred to as pdf optimized quantizer. Channeloptimized vector quantization covq is a well. Optimized quantizer with matlab program pdf optimized quantizer. Distance quantization method for fast nearest neighbor search. For the system shown in page 10, calculate theoretically. Figure 3 f shows the circuit layout of second order sdm in simulink. Effective modelling of higher order sigma delta adc using.

Dataweighted averaging dwa, using a 4stage logarithmic shifter, shapes the mismatch errors of the 15level dac. In the following sections, we construct estimators by applying methods of convex optimization to the observed output of a firstorder sigmadelta modulator. The high builtin gain of the bf quantizer allows neural signals to be measured with a modest afe circuit. Kim 1 1department of electrical and computer engineering, 2department of neuroscience, 3department of biomedical engineering, university of minnesota, minneapolis, mn 55455 usa. Quantizers with nonuniform step sizes can be beneficial in cases when. The lloyd max algorithm 10 is a wellknown approach to designing nonuniform quantizers optimized according to the prevailing pdf of the input signal. The schematic of a memoryless quantizer is shown below. Let quantization levels be the midpoint of the quantization regions except. The quantization operation is performed by digital comparators or sampleandhold circuits.

Model of a gaussian source with successive quantizer and buffer memory. A key element of the adc structure is a 5bit vcobased. Sample and hold circuit, comparator, transmission gate, hybrid adc, twostep quantizer. Optimal uniform quantizer given the number of regions, n find the optimal value of. Recently, continuoustime ct adcs gain growing interest in wireless. Ratedistortion optimized quantization is encountered in source coding for lossy data compression. Assuming that you know the pdf of the samples to be quantized design the quantizer s step so that it is optimal for that pdf. Figure 3 e shows the analog input signal and output signal of fifth order sdm.