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31 Threads found on Sine Lookup Table
You can have look at the basic working theory @ Its implemented for LPC2148 but the underlying working is the same. You need to generate or use a hardcoded sine lookup table which feeds values to your PWM block and at the PWM output use a filter which acts a D
Thanks for the reply. I didn't quite understand some of it. So you're saying that you take two VCOs and mix them together (one of which is a voltage controlled cavity resonator)? What did you mean by "offset by the fmax"? In my example (1 MHz to 5 GHz), can you give some numbers? I can imagine that you could mix together two oscillators, one tuna
hi frnds i wan to make v/f control of 3phase acim successfuly i generate 3 phase sine wave, which frequency can vary frm 1hz to 1023hz using 3 phase DDS by sine lookup table, timer,interrupt. now i wana to implement V/F i attached my program (...)
I need to know how to send saved data in lookup table to audio codec of de2-70 altera kit line out in VHDL.
You could use a lookup table with just a quarter of the complete sine, or you could use linear interpolation for the same quarter. for the interpolation, you could save just the "m" and "b" parameters of the "y=mx+b" equation
How the lookup table values are created to vary the duty cycle accorging to sine amplitude
The basic principal is that, after filtering, a narrow pulsewidth will yield a low voltage and a wide pulse width will yield a high voltage. Your lookup table will be a table of pulse-widths that correspond to the levels of your sinewave. For example, lets say you use a 36 element table. Each element (...)
how to generate sinewave with verilog code
hello I am designing a smps based sine wave inverter of 500VA 220v/50Hz. i have succefully designed DC-DC converter stage. my aim is to convert 311VDC to 220V ac sinusoidal. for this ,i have designed a H-BRIDGE driven by a UNIPOLAR SPWM. i am using a microcontroller (DSPIC33FJ32MCPWM) to generate the UNIPOLAR SPWM of 20KHz carrier and 50Hz
You put the lookup values for the sine wave (voltage versus time increment) in the table for the piece-wise linear generator.
Hello Mr. Mithun, To generate pure sine with 16F73 you must need a lookup table using calculated sine point. Because 16F series doesn't have enough speed to calculate Multiplication for (i=0; i<15; i++) { teta = ( (float) i / 15 ) * 3.14159; sample = (int) (255 * sin ( teta )); PWM1_Set_Duty(sample); } Try this (...)
Depends on how you generate the "pwm waveform". The phase shift applies to the modulating sine waveform, not the pwm carrier. Assumed you are generating the sine by a lookup table, the 120 and 240 degree phase shift isn't but an offset to the table index.
HI rikotech8. For 3 phase sine wave inverter it needs 6 complementary sine modulated output with deadtime generation. which is already implemented in hardware of 18F2431 architecture. You just have to set corresponding SFR's and a sine lookup table which will fed sine modulated PWM duty (...)
Take a look at this URL
Arun, You must to calculate and generate a sine map to record into a table in order to sample at DAC device. +++
hi to all can any one can help me to create sine lookup table to generate 3 phase spwm
It sounds as though you're using a method that will have lookup tables consisting of partial sine waves. First and last values may be far apart. This will result in sudden transitions at the speaker. You'll get harsh sounding sine waves. You only need one lookup table. You stated your (...)
I would also consider a lookup table. But if you want to use taylor series (and the sine doesn't need to be exact), with a bunch of multipliers, a couple of adders and some dividers, you can do the trick... sin(x) = x + x^3/6 could give a result close enough (if you known beforehand what angles you're dealing with). regards
Hello. The switching frequency of my inverter design very high that the frequency ratio irequires the use of 420 steps in the lookup table.The question is for pic16f877 is the memory and resolution sufficient to cater for this table as well as the main PWM program in asm.
what frequency do you require ? I have used a MCP41010 digital potentiometer to generate a 3KHz sine wave MCP41010 if you need a higher frequency a DAC (Digital to Analogue converter) could be used
One possible way is to calculate the table in VHDL at compile time, as shown in the below example. (It's a 0..pi sine table, not the solution for your problem). TYPE SINTAB IS ARRAY(0 TO ROMSIZE-1) OF STD_LOGIC_VECTOR (NNCO-2 DOWNTO 0); SIGNAL SINROM: SINTAB; BEGIN GENROM: FOR idx in 0 TO ROMSIZE-1 GENERATE CONSTANT x: REAL := SI
i cannot increase the frequency more than around 1kHz. i am using 64 sampled look-up table. 20MHz crystal. how can i increase the sample rate to get 10kHz sine wave. (that is sample rate at 1.5625 micro sec/sample)
hello friends... i have to generate 3 waveforms : 1.sine wave of 50 hz 2.square wave of 50 hz 3.square wave of 12khz. first two waveforms need to have same starting point. Please suggest what to do generating sine wave by lookup table and dac ,a good method .Please suggest how to synchronise. Ithink i have to (...)
;********************************************************************* TITLE "PWM based sine wave generator" LIST P=16C620, R=DEC INCLUDE __CONFIG _BODEN_OFF&_CP_OFF&_PWRTE_ON&_WDT_OFF&_XT_OSC ; ;********************************************************************* ; File: sine.ASM ; Author
First of all, you do not need to change the lookup table (the table where you store the sine wave values) as the output frequency changes. The waveform will be always the same, the only change will be the speed that the points of the table are converted to analog signal. The solution for your problem is the (...)
the diagram below shows my design to generate a sine wave ... but its not generating it .... help needed there any need to create a lookup table inside the DDS block .. or its there by defalult ...? If it is required to create a lookup table manually then h
Hi, i think the best way to do this is to make a lookup table with stored digital values of a single cycle of a sine wave and raster on this value with ur required frequency, also offcourse u need DAC to get ur analog signal. good luck.
Easy way... Write a lookup table in memory and use a pointer, the lookup table contains the precalculated values for a sine wave, as example 256 values for a 8bit DAC (128 values are also working...). For each phase you want to create use a seperate pointer on the lookup (...)
I want to design a digital signal generator which can generate digital values for the sine wave using 8051 and then convert it to analog sine wave using DAC0808. But how to compute values for a function x = sin(w n) using 8051 if i want 50 samples per cycle and 100 Hertz frequency of sine wave. I don't want to use lookup (...)
hi wagewage , let me know about how to use DW cosine and sine function? how its works? if u dont wanna use that function. how can i write my won code for cosine and sine function in combinational. sorry i dont know to answer ur questions. thanks in advance aravind You can either use a lookup (...)
1. a lookup table located into a PROM; practically the address data is the input value and the output data is the "computed sinus"... 2. use the nonliniar region of a dioda. 3. do a polinomial serie sine aproximation. hope this helps, //a

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