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# Fractional System

9 Threads found on edaboard.com: Fractional System

## How to read signed values from FPGA in VHDL to Nios II system

You should change the hardware to give the Nios a 16-bt signed value by doing the sign extension external to the Nios. Thanks for your reply... But, the 14-bit data can be positive, zero or negative. The 14-bit-data is defined as follow: with msb as the sign bit, the following 6 bits are the magnitude for integer and

## range of values for fixed point numbering

With N bits, you can represent 2^N equally spaced numbers in fixed point. Which are those numbers is a matter of the numbering system or representation, for example: * Positive integers from 0 to 2^N-1 in unsigned integer format * Integers From -2^(N-1) to -2^N-1 in signed integer format * fractional numbers from -1 to +1-1/(2^(

## quantization and how to determine the fixed point bit?

Number A is the input of the system, let's assume it's 0.123456. After the double precision number A has been processed in the system, I get the double precision result B(the actual result). To get where my fixed point is, I apply the following procedure: the final form is Q1.(N-1), which means 1bit for sign, N-1 bit for fractional (...)

## dspic33f PWM resolution conversion introduces jitter in PWM output

It looks like the device implements fractional divider methods to achieve average time resolutions smaller than the system clock period. In this case, jitter will be an unavoidable side effect. But it's only a guess, I wasn't able to find the PWM generator details at a brief datasheet review. I think, Microchip didn't manage to present them clearly

## need PLL scheme or special solution to fit the requirements

Hi,I don't know what do you mean by high resolution.which is usually defined by the hopping frequency around the center frequency.For example,in bluetooth system the local oscillator could lock at 2.4G~2.525G with 1M resolution. 1ppm resolution means that your hopping frequency is 2.5k. fractional-N is needed here.Because 1us locking time is

## frequency synthesizer general questions

Hi all When I was doing the frequency synthesizer dimensioning (N-fractional synthesizer) in system level design (WiMAX standard, 3.4-3.6GHz, 10MHz the channel bandwidth), I found some ambiguity regarding the reference frequency and the division period (T=Fref/channel space), For example how can I choose the Fref? I know that Nfrac=Fout/Fref,

## trobled with the system parameter design of fractional-pll

we wanna design a fractional pll with ring oscillator. the input frequency is from 5M to 50M, and we set the bandwith to be 50khz, the segma-delta modulator is 3th order. the current ICP is varying with the N which varies from 1 to 128 the troble we meet is by calculation the Cs in the LPF is more than 1uF!, if we want the phase margin more tha

## fractional_N PLL realization

Does anyone has the experience on fractional N PLL design? it seems very difficult to implement it in a chip for me. many papers have describled the FN-PLL principle, but few of them refer to the detailed realization methods.Can anybody give me any advice ? such as what is the design flow, which tool should be to use, and any good articles on th

## [Ques] Sigma Delta Fractional-N Synthesizer in ADS

attached is a "DELTA SIGMA fractional-N Synthesizer" design Project created by @DS 2005A Design Guide. hope can help you....:D