Electrical Engineering Stack Exchange
Electrical Engineering Stack Exchange

Questions tagged [dds]

A direct digital synthesizer (DDS) creates waveforms from a single frequency reference clock. Typically the reference frequency is fed into a numerically controlled oscillator (NCO) that controls the final frequency and waveform type from where the quantized digital data is converted to analog using a digital to analog converter (DAC).

80 questions
14
votes
5 answers

Driving 50W-250W ultrasonic transducers with sine: Any Class B 135KHz monolithic power amp ICs?

My project needs to drive a medium power ultrasonic piezoelectric transducer from a sine wave (/ sawtooth) sweep generator that sweeps +/- 2% of the transducer resonant frequency. The question: What are my simplest options for driving these…
Anindo Ghosh
  • 50,188
  • 8
  • 103
  • 200
10
votes
2 answers

How to design a cheap sine-wave generator up to 200 MHz?

I want to make a cheap wideband oscillator for an antenna analyzer I'm designing. I want a simple sine wave over a wide frequency range. I don't want to use a DDS IC like the AD9851 because it's expensive and feels like overkill. I was looking at…
bcattle
  • 233
  • 2
  • 8
8
votes
2 answers

Accuracy problem of a DDS at very low frequencies

First time in my life I'm using this DDS chip (AD9850) to create sine wave at a desired freq, where I upload the lookup table code and the desired freq. command via a with micro-controller. So my knowledge at the moment very limited. The thing seems…
floppy380
  • 1,715
  • 7
  • 33
  • 67
8
votes
2 answers

What kind of effects does a relay have on signals?

Currently I'm working on a DDS based function generator. The idea is to use an AD9834 chip that will generate a triangle/sine or square wave. With some amplification electronics I want a configurable frequency, offset and amplitude. I have no set…
Hans
  • 7,238
  • 1
  • 25
  • 37
6
votes
1 answer

LC filter vs Isolation tranformer for AC coupling of a DAC output

I'm trying to decide between a few choices for coupling the output DAC of a DDS with the rest of my circuit. DDS dac's I'm looking at are typically either single-ended or have complimentary current out ports. The signals I'm trying to produce are…
crasic
  • 5,797
  • 1
  • 20
  • 43
4
votes
5 answers

Fast (high) frequency hopping with off-the-shelf components

I am looking for the easiest solution to synthesize 1.6 - 2.4 GHz (qudrature) in steps of 4 MHz settle within 10-50ns precise timing control when to switch frequency (e.g., at rising edge of an external signal, frequency should be updated) total…
divB
  • 1,312
  • 14
  • 32
4
votes
3 answers

Replacing Crystal Oscillator with DDS.

In a circuit like this, can the crystal oscillator be replaced with a DDS such as a AD9850? If so can it just be dropped in or would other components have to be changed? Second question, how sensitive are simple transceivers like this to slight…
user701329
  • 53
  • 2
  • 5
3
votes
1 answer

What is the output amplitude of direct digital sythesizers such as the AD9850?

When looking at AD9850 DDS or other similar parts made by Analog Devices, it is obvious that the output signal amplitude changes with frequency. This can be shown as \$x= \pi \dfrac{f_{out}}{f_{clock}}\$ and amplitude changes by \$\dfrac{\sin x…
Aug
  • 1,561
  • 6
  • 28
  • 63
3
votes
2 answers

UHF Phase Modulation

I would like to design a system that produces -10 degrees and +10 degrees phase shifts at 409.6MHz (Basically BPSK). The way I'm thinking about approaching this is by using a DDS to generate the BPSK at 12.8MHz and up-converting using a mixer to…
hassan789
  • 2,106
  • 4
  • 21
  • 34
3
votes
1 answer

AD9833 Problems with Arduino and SPI [Can't think of a good title]

Alright I'm about at my wits end, I'm playing around with a AD9833 to synthasize a sin wave. I have combed though all forms of forums regarding the AD9833 to no avail. This is the circuit I'm running. EDIT: although the circuit says Fsync is…
Lpaulson
  • 165
  • 2
  • 11
3
votes
4 answers

Generating a sine wave over a big frequency range

I want to build a circuit that can generate sine waves at frequencies controlled by a computer or a microcontroller. I would like to go as low as 0.01 Hz (down to 0.05 Hz would probably be acceptable) and as high as 100 kHz; I need at least 10…
Greg d'Eon
  • 3,807
  • 4
  • 24
  • 50
2
votes
2 answers

How to protect a signal from output short circuit?

I have made a signal generator based on DDS and amplified its output to 0-20 V pk-pk. Now I want to prepare the output side. My main concern is short circuit protection to prevent damage to my device. I was thinking about isolating the signal on the…
Aug
  • 1,561
  • 6
  • 28
  • 63
2
votes
1 answer

AD9850 just works for a few minutes?

I am trying to drive AD9850 (DDS). First I started with a module , programmed the micro (ATMega128 ) and everything was ok ( It means there may not be a software error). Then I decided to make my own PCB (because the module has inbuilt low pass…
Aug
  • 1,561
  • 6
  • 28
  • 63
2
votes
2 answers

Sawtooth/ramp waves with fixed amplitude from sine or square clock source?

I hope someone can help me out! A bit of background info: I have created a DDS based signal generator (Using PIC MCU to drive a AD9833 for DDS output). The generator is capable to produce sine, triangle and square waves up to 12.5Mhz. However the…
Osvaldo
  • 21
  • 1
  • 2
2
votes
2 answers

Implementing direct digital synthesis in STM32 microcontroller

I am working on a project that requires phase locking (digitally) of an output signal from a sensor to the reference signal which needs to be done on STM32 microcontroller. I am new to this area, and just read some basic theory behind phase locked…
Rima
  • 135
  • 5
1
2 3 4 5 6