arduino signal generator

Projects General Guidance
1

I am making a function generator with arduino mega and adalog device ad9850. However, I had just made the sine and square wave.

1.May I ask is it possible to make triangle wave with these device?

  1. I use rotary encoder to adjust the frequency successfully. Can I change the amplitude with these device?

Many thanks.

2

If you can generate a sine wave you can generate a triange wave.
increment from 0 during first half of period to maximum, decrement during second half
press the rotary encoder button to switch between control of frequency and amplitude

3

horace:
If you can generate a sine wave you can generate a triange wave.
increment from 0 during first half of period to maximum, decrement during second half
press the rotary encoder button to switch between control of frequency and amplitude

The AD9850 uses DDS techniques to generate a sinewave. It is not just a DAC.
Kkjoker, Why do you want to generate triangle waves? Is it just because other signal generators sometimes do?
In the 40+ years I've been in the electronics industry I've never needed a triangle wave generator.

4

horace:
If you can generate a sine wave you can generate a triange wave.
increment from 0 during first half of period to maximum, decrement during second half
press the rotary encoder button to switch between control of frequency and amplitude

Can you explain more about how can adjust amplitude with arduino, ad9850 and rotary encoder？

5

kkjoker:
1.May I ask is it possible to make triangle wave with these device?
2. I use rotary encoder to adjust the frequency successfully. Can I change the amplitude with these device?

  1. No
  2. No

The AD9850 generates a sinewave by DDS, you can square the output with the comparator in the AD9850.
You cannot change the amplitude or generate other waveforms directly.

Yours,
TonyWilk

6

TonyWilk:

  1. No
  2. No

The AD9850 generates a sinewave by DDS, you can square the output with the comparator in the AD9850.
You cannot change the amplitude or generate other waveforms directly.

Yours,
TonyWilk

If i want to do so, what can I use instead of Ad9850？

7

kkjoker:
If i want to do so, what can I use instead of Ad9850？

There's a whole bunch of Analog Devices - DDS Waveform Generator parts.

Yours,
TonyWilk

8

I am sorry that I really need help. I check AD9833 can replace AD9850 to geneate 3 waveforms. However, I am not sure how can I adjust the amplitude by Arduino. Can anyone teach me？

9

TonyWilk:

  1. No
  2. No

The AD9850 generates a sinewave by DDS, you can square the output with the comparator in the AD9850.
You cannot change the amplitude or generate other waveforms directly.

Yours,
TonyWilk

What component can I add for the amplitude control？ Can you give the example cod as I really have no idea on it

10

kkjoker:
I am sorry that I really need help. I check AD9833 can replace AD9850 to geneate 3 waveforms. However, I am not sure how can I adjust the amplitude by Arduino. Can anyone teach me？

You could use something like the AD5171, see: Digital Potentiometer

Yours,
TonyWilk

11

The version of Ad9833 development board I bought from ebay, includes a MCP41010 8-bit digital potentiometer and an opamp. It seems that it can boost and control the amplitude of the output？

Is there any sample of Ardtino code for this module？ Many thanks.

AD9833 board
https://m.ebay.com/itm/AD9833-DDS-Signal-Generator-Module-0-12-5MHz-Square-Triangle-Sine-Wave-/201754842635

12

kkjoker:
What component can I add for the amplitude control？ Can you give the example cod as I really have no idea on it

I used a TDA8551 NXP Audio Amplifier in a similar project
AF Amplifier With Digital Volume Control Based On TDA8551

13

not gonna get much bandwidth..... I'm betting he thinks he's build a 1hz to 20mhz generator with just the two boards (ardu & dss).

If he gets far enough with an amp on the backend, his next post will be wondering what happened to his output signal when he tried to go into rf range,,,,,