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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).

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I have a AD9833 function generator which has the ability to change frequency from 1k to 1MHz but a fixed 0.6V output I want 1V to 10V pk to pk

The frequency changes from the AD9833 DDS chip but it has a 0.6V pk to pk and I need it to be 1V to 10V pk to pk this is my circuit so far the goal is to have an adjustable gain please any adjustments ...
zug's user avatar
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How can I generate a 100kHz sine wave on FPGA?

I am performing direct digital synthesis on my FPGA using lookup tables, and jumping through them to increase output frequency. As the value of the phase accumulator increases, the sine wave becomes ...
DaveFenner's user avatar
1 vote
1 answer
146 views

Adding programmable amplitude control to an AD9833-based function generator

I'm working on making a function generator using the AD9833 DDS chip, but it doesn't have programmable amplitude control. I want to use external hardware to achieve this. My amplitude has to be 1 V to ...
zug's user avatar
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3 answers
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Calculating audio sample output rate for synthesizer

I'm building a synthesizer on an FPGA and I'm having trouble calculating sampling rates. Currently, I'm running a system clock at 98.3 MHz and I want to produce 16-bit audio at the output. I've got a ...
Andrew Li's user avatar
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What is the purpose of this long capacitor/inductor chain on a DDS IC evaluation board?

Image of the B output stage of the EVAL-CN0304 AD9834 DDS Evaluation Board IOUT_B is a current source, not potential source, so the initial say half of the circuit I get. The resistor gives us a ...
thomasaronford's user avatar
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56 views

How to avoid distortion (quantization error) in DDS output in STM32?

I have been using a timer interrupt to generate sine waves with an STM32, however, for higher phase increments (to get higher frequencies as output), there are quantization errors (distortions). To ...
Rima's user avatar
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1 answer
369 views

How to generate correct frequency in DDS using stm32?

I had asked a question a week ago regarding DDS on STM32 and I got some good answers. Based on that I tried to write a code to implement DDS on stm32. In my project I need to generate a 10 KHz sine ...
Rima's user avatar
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2 votes
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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 ...
Rima's user avatar
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UTG900E output specification

The datasheet of UTG900E Waveform generator says it can output up to 10 Vpp on a 50 ohm load, but in chapter 3.3.1 is stated the load can be set between 1 and 999 ohm. Nowhere in the datasheet I see ...
Mark's user avatar
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How to increase SFDR value for Direct digital synthesizer simulation?

I am following the code written in this article code and I am manipulating some numbers based on my application. I want to use a stm32 microcontroller to generate a sine waveform. I didn't understand ...
Rima's user avatar
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Confusing about impedance termination

Datasheets by analog devices state that I must terminate IC (AD9910) impedance by input impedance of 50 Ω and placement near the balun. But here is the deal when I was looking for AD9912 datasheet (...
Settasak's user avatar
2 votes
1 answer
238 views

How to calculate RMS noise from datasheet?

I am using an AD9833 DDS as a sine signal source for my circuit. The bandwidth will be 3.5MHz. I would like to calculate the RMS noise of the DDS for my bandwidth. The datasheet has a SNR ...
FrüchteTony's user avatar
2 votes
0 answers
124 views

DDS reconstruction filter after amplifier?

I need a clean sine wave from 10 kHz to 2 MHz as an excitation source for an eddy current probe. The sine wave will be generated by an AD9833 DDS with a clock frequency of 25 MHz. As a reconstruction ...
TonyDublov's user avatar
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DDS example of a reference tone's frequency muliplied by 12000 to generate a master clock

A free project RAM Platter Hybrid aims to generate a master clock from a tone which is 12000 times lower in frequency. The reference tone is 1 kHz at its central frequency. It will have a minimum of 0 ...
Matt's user avatar
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3 answers
171 views

DDS output power

I am designing a circuit that uses a DDS (AD5932) and am having trouble finding its output power. I need to know the power because the output will be fed into a mixer with characteristics that depend ...
brunerm99's user avatar
2 votes
1 answer
130 views

Confusion on what the RF input to a PLL does

I am designing an FMCW radar, for which I need to generate an RF signal ramped in frequency. To accomplish this, I want to use a direct digital synthesizer (DDS) to generate the ramp at baseband then ...
brunerm99's user avatar
1 vote
1 answer
193 views

DDS - find optimal size for LUT, PHACC and sampling freq for application

I had the following question. About the topic of DDS you can find a bunch of information on the net and i think i understood the basics relatively well. You use a lookup-table with stored values of ...
Rabobsel's user avatar
2 votes
0 answers
117 views

DDS NBFM transmitter design

As a design exercise I'm trying to come up with a design for NBFM. I'd like to stick with digital domain as much as possible, since that's what I know best. I'm familiar with RF enough to know that I ...
entropiae's user avatar
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1 answer
185 views

Multiple Direct Digital Synthesizers (DDS) to Increase Sample Rate

I’m looking to generate a RF signal sampled at around 10 GSPS operating above the 3GHz mark. In order to maximize data throughput, the signal will be modulated at that frequency (rather than mixing in ...
monibius's user avatar
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1 answer
170 views

How to use same low pass filter for square and sine wave

I'm trying to desing simple DDS waveform generator using DDS IC, but I'm a bit lost about designing output filter for it. My requirements are 1 Hz - 25 MHz sine, square and triangle/ramp wave. Using ...
Poseydon's user avatar
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427 views

Amplify 1kHz sine wave from AD9833 DDS using LMH6609 operational amplifier

I'm trying to amplify a 1kHz sine wave signal from the AD9833 DDS chip (0.6Vp-p) to a more usable level (6Vp-p) for a sort of function generator. I plan to work with higher frequencies as well. So I ...
Harid444's user avatar
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1 answer
154 views

Reference clock of 400 MHz oscillator or 20 MHz and multiply by 20?

I am trying to design a sinusoidal signal generator using AD9954 which is a Direct Digital Synthesis (DDS) with takes a maximum of 400 MHz crystal oscillator as reference frequency. It also has a ...
David Norman's user avatar
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How does stretch processing work for SFCW?

I've been reading about FMCW radar, and I understand that a chirped signal can be de-chirped by mixing it with a copy of itself, which yields a beat frequency which is much easier to process and is ...
user201537's user avatar
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381 views

VHDL error during synthesis, declaration and syntax error

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sangeeta's user avatar
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1 answer
200 views

How to correctly configure AD9951 for 10Vp-p, 100Mhz sinusoidal waveform

I am trying to build a function generator for sinusoidal waveform with frequencies ranging from 1 Khz to 100 Mhz with amplitude of about 4 Vp-p to 10 Vp-p. I have been looking at AD9951 DDS that takes ...
David Norman's user avatar
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1 vote
1 answer
171 views

What causes 100Hz spuriour emissions on AD9850 WSPR transmitter?

I've built WSPR transmitter based on AD9850. AD9850 is driven by 125 MHz crystal. TX frequency is 14 Mhz. On the receive side there is upconverter (+125 MHZ crystal) and SDR (both RTL-SDR and AirSpy). ...
BarsMonster's user avatar
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1 vote
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131 views

Ripple on tens-millivolts sinus waveform

I’m trying to make a DDS to generate a sinusoidal signal with tens to hundreds of millivolt amplitude and hundreds kHz frequency using an LTC1666 DAC. But I have some confusing results. Device ...
Andrew's user avatar
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0 answers
284 views

How to find the RMS value of a sine wave with DC offset and retain the negative sign

I'm trying to build a Quadrature setup where an input signal is mixed with a reference signal that is in-phase and another one out-of-phase by 90deg. The idea is to extract the real and imaginary ...
leviathan's user avatar
8 votes
2 answers
1k views

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 ...
floppy380's user avatar
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1 vote
2 answers
131 views

Is this an artifact of DDS technique?

When I sample a sine wave output of a DDS based bench function generator I have noticed there is always harmonics of the fundamental frequency. For example, below is the function generator's output ...
floppy380's user avatar
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0 votes
1 answer
120 views

How is the tuning-word of a DDS sent and coded?

I have read that a DDS have two inputs one for master clock another for the tuning word. By processing these two inputs the DDS generates the output waveform at a desired frequency. And if I'm not ...
cm64's user avatar
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1 vote
0 answers
218 views

Frequency response of linear DDS chirp

I am performing a linear frequency sweep from 80 MHz to 120 MHz in 26.84 ms with the AD9910 direct digital synthesiser. I experience that the output amplitude is not constant (see Figure 1). With my ...
bodokaiser's user avatar
4 votes
5 answers
875 views

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 ...
divB's user avatar
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1 vote
1 answer
618 views

direct digital synthesis low pass filter

I am designing a sine wave generator using a dds chip (ad9833). The system parameters are: frequency range of 1-12 MHz spurs and harmonics down to -50 dBc Output power atleast 10 dBm Since the ...
michael johnson's user avatar
1 vote
5 answers
616 views

Can I combine a PLL and a DDS?

I need a controllable frequency for use in a radio transceiver with a range of 3–50MHz (i.e., 80m–6m). The frequency needs to be selectable using a microcontroller. Because chips like the Si5351 tend ...
user avatar
0 votes
1 answer
1k views

Low-Pass Filter Cutoff Frequency

In the context of direct digital synthesis, I need a low pass filter to reconstruct the analog signal at the output of a DAC. I'm generating only sine wave signals and the maximum carrier frequency is ...
geschema's user avatar
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0 votes
1 answer
451 views

AD9850 Harmonics at Lower Frequencies

I am wanting to use the AD9850 for a particular application to generate sine wave signals in the 100Hz to 5kHz range. I've purchased a AD9850 module from ebay which just looks like the standard ones ...
CakeOrDeath's user avatar
1 vote
2 answers
222 views

Input clock of a Direct Digital Synthesizer

I need to create a circuit based around one of Analog Digital DDSs (AD9102) to create a sinusoidal signal at 150kHz. For this purpose I think that a clock line at around 10MHz would be sufficient. I ...
NotSure's user avatar
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0 votes
1 answer
361 views

Incorrect signal from signal generator H11887 DDS

I'm a newbie in engineering. I bought this generator on ali and built it. Problem in signal from DDS out: it has incorrect form. I don't have +/- power supply so tested only on +5V. Reasons could be:...
Artem Aleksashkin's user avatar
0 votes
1 answer
441 views

Formatting DDS Sine Wave output to unsigned decimal

Currently, I am working with the DDS core on Vivado, using Verilog, to generate a sign wave using a phase width of 7 and output width of 12. I understand that DDS formats the output in 2's complement /...
stephchia's user avatar
0 votes
1 answer
73 views

K50-HC0CSE25.0000MR Clock signal not being driven to correct logic levels

I am using a K50-HC0CSE25.0000MR to generate a 25MHz clock for the DDS IC AD9833. I have hooked up the clock output directly to the MCLK input of AD9833 as shown in the diagram.. The data sheet ...
user1155386's user avatar
10 votes
2 answers
11k views

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 ...
bcattle's user avatar
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0 votes
1 answer
164 views

tvalid delay in AXIS

I am trying to feed the cosine wave from the DDS compiler to the multiplier and multiply with another cosine wave. The output of the multiplier is then feed into a CIC compiler as shown below. I have ...
user9870's user avatar
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3 votes
1 answer
3k views

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. ...
Lpaulson's user avatar
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0 votes
2 answers
1k views

Using the AD9833 for a 2MHz square wave

Will I be able to accuratley generate a 2MHz square wave using the AD9833 (pdf data sheet) ? I know that as you approach the clock frequency on a DDS you get distorted output signals. I was just ...
TomJ's user avatar
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1 vote
1 answer
668 views

BPSK modulator with DDS on FPGA

I was developing a BPSK modulator with an AD9852. Since AD doesn't seem to offer any way to functionally simulate their DDS ICs, suddenly i see myself in the need to change for a FPGA architecture. I ...
Alejandro's user avatar
0 votes
2 answers
1k views

Unnatural AD9850 Output Attenuation

Yes, another question about this DDS. However, I think mine is sufficiently different from the others I've read. I purchased an AD9850 board on Amazon for $17 from "NooElec" (see here). I've been ...
wisner's user avatar
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-3 votes
1 answer
379 views

How to design a suitable low pass filter for different waveform

I want to realize a DDS signal generator based on FPGA,which is composed of FPGA,DAC and low pass filter,and the FPGA control a DAC to output different kind of signal. Here are the system performance ...
samson's user avatar
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1 vote
1 answer
549 views

Digital potentiometer as INA129 gain

I'm working on a waveform generator for which I'm using the DDS AD9833 chip to generate sine signals and triangular signals. I'm trying to amplify these waves since the AD9833 output is 600mVpp and I ...
JsMartinez's user avatar
1 vote
3 answers
1k views

Calibrating a TCXO

I'm looking at using the si5351 in a signal generator. It will use a TCXO for improved stability, but I'd still like to calibrate it occasionally. To that end, one of the clock outputs will be set to ...
Alan Campbell's user avatar