Direct Digital Synthesis: The Accumulator  ADI  DigiKey
07/03/2013 · Preview of ADI's Direct Digital Synthesis Tutorial Series (2 of 7): The Accumulator PTM
All About Direct Digital Synthesis  Analog Devices
N2  A new full simulation, design and verification of a Direct Digital Frequency Synthesizer (DDFS), utilizing only one quarter of a given sinusoidal wave, are presented in this study. A reduction in the size of the LUT is accomplished as the new design requires storing only a quarter of the sine wave. The Register Transfer Level (RTL) and the Gate level is implemented by the Quartus II. The Quartus II will then invoke the ModelSim Altera software to simulate the output. The DDFS consists of three major models, mainly a Phase Accumulator (PA), a Phase Register and a Look Up Table (LUT). All of the mentioned models are realized by a Verilog code. The spurious free dynamic range is achieved with a value of 73 dB using a 16 bit phase accumulator. The proposed design is verified through the application of different input frequencies and obtained results showed that output frequency is directly proportional to the tuning input frequency.
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A new full simulation, design and verification of a Direct Digital Frequency Synthesizer (DDFS), utilizing only one quarter of a given sinusoidal wave, are presented in this study. A reduction in the size of the LUT is accomplished as the new design requires storing only a quarter of the sine wave. The Register Transfer Level (RTL) and the Gate level is implemented by the Quartus II. The Quartus II will then invoke the ModelSim Altera software to simulate the output. The DDFS consists of three major models, mainly a Phase Accumulator (PA), a Phase Register and a Look Up Table (LUT). All of the mentioned models are realized by a Verilog code. The spurious free dynamic range is achieved with a value of 73 dB using a 16 bit phase accumulator. The proposed design is verified through the application of different input frequencies and obtained results showed that output frequency is directly proportional to the tuning input frequency.
Direct Digital Synthesis  Analog Devices
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Hardware To generate a fixed frequency style, we start out with a clock source which just generates a pulsetrain of fixedfrequency square waves which clock the binary counter whose output is connected to the digital to analogue converter ().
To keep things simple, we use a 16Hz clock frequency, a 3bit counter and an whose output voltage is equal to the counter’s output. In terms, the counter is known as the phase accumulator.
The triangle channel’s output corresponds to Timer0’s PWM output on OC0B. The method used to generate triangle wave samples is identical to the direct digital synthesis scheme used to generate pulse wave samples: during every other overflow, if the triangle channel is not silenced, a 16bit t_accumulator is incremented by an amount determined by the requested note frequency. t_sequencer is obtained by rightshifting the result, and is used an index into a triangle waveform sequence of length 32. This sequence takes on 16 possible values; it counts down from 15 to 0, and then from 0 back up to 15. The resulting value is scaled to a number between 0 and 255 and then written to OCR0B, updating the PWM output corresponding to the triangle channel.
Basics of Direct Digital Synthesis  DigiKey
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LUT: ( length: m, length [memorywidth]: n ), called also digital PhasetoAmplitude Converter(PAC), or polartorectangular transformation (projection of the real orimaginary component in time), or (sine) waveform mapping device  a MEMory.
Here we model all techniques of calculating data as simple lookup table operations.
The lookup memory contains one cycle of the waveform to be generated.
For practical considerations, only the high bits of the ACC are sent to indexthe LUT ( the size of the LUT is 2^{m} words, phase truncation: m r ). LUT translates truncated phase information, being in digital form ( see ), into quantized numerical waveform samples  this is the most challengingpart of NCO.
phase resolution (m  bit) has to match with the amplitudeprecision (n  bit).
The pulse channel’s output corresponds to Timer0’s PWM output on OC0A. The pulse channel is implemented using the following direct digital synthesis scheme: During every other overflow, if the pulse channel is not silenced, a 16bit p1_accumulator is incremented by an amount determined by the requested note frequency. p1_sequencer is obtained by rightshifting the result, and is used as an index into a pulse waveform sequence of length 8. The result is scaled to a number between 0 and 255 and then written to OCR0A, updating the PWM output corresponding to the pulse channel.
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Direct Digital Synthesis Primer

May 2002 13 .Fundamental DDS Architecture How Many Phase Bits
Documentation

The result is a Direct Digital Synthesis implementation.
Abkürzungen  Info

Direct Digital Synthesis  Sine  Digital To Analog Converter
ECE 4760: Chiptune Mega Mega
Direct Digital Synthesis (DDS) ..
Direct Digital Frequency Synthesis (DDFS or simply DDS), also knownas Numerically Controlled Oscillator (NCO), is a technique using digitaldataand mixed/analogsignal processing blocks as a means to generate reallifewaveforms that are repetitive in nature. It is used especially for a precise,fast frequency and phase tunable output. DDS solutions can be implementedin LSI (largescale integration) and they play an everincreasing role indigital waveform and agile clock generation, and modulation.
As a discretetime and discreteamplitude system, DDS roots from sampling and quantizing theorems.
What is DDS  Direct Digital Synthesis  Electronics Notes
AB  A new full simulation, design and verification of a Direct Digital Frequency Synthesizer (DDFS), utilizing only one quarter of a given sinusoidal wave, are presented in this study. A reduction in the size of the LUT is accomplished as the new design requires storing only a quarter of the sine wave. The Register Transfer Level (RTL) and the Gate level is implemented by the Quartus II. The Quartus II will then invoke the ModelSim Altera software to simulate the output. The DDFS consists of three major models, mainly a Phase Accumulator (PA), a Phase Register and a Look Up Table (LUT). All of the mentioned models are realized by a Verilog code. The spurious free dynamic range is achieved with a value of 73 dB using a 16 bit phase accumulator. The proposed design is verified through the application of different input frequencies and obtained results showed that output frequency is directly proportional to the tuning input frequency.
This chapter introduces direct digital synthesis ..
A harmonic signal generator with adjustable frequency, phase and harmonic proportion is designed in this paper.
Key words: ARM 7, (DDS) Direct Digital Synthesizer (AWG) Arbitrary Waveform Generator, function generator
Reference
[1] Amauri A Assef1 Joaquim M Maia1, Fábio K Schneide (2013) A reconfigurable arbitrary waveform generator using PWM modulation for ultrasound research
[2] Mr.