to making oscillators


I want to make a oscillator that 1mhz to 2 mhz But arduino is 16 mhz device. So I couldn't make a specific frequency like 1550khz and 1420 (just example) So I want to operate it with at least 48mhz. So what I think is using 3 analog port I'm planing to use multi plexer and clock. Is there any simple way to make my project?

I want to make a oscillator that 1MHz to 2 MHz But arduino is 16 MHz device.

DDS signal generators are dirt-cheap.

My Uno works at 16MHz, no problem with mHz :-]

It is true that arduino can operate 16mhz But I want to make good spatial resoulation oscillator. So I look ad9850 that has125 mhz clock rate The clock pin in ad9850 is seem to connect digital ppin I didnt understand its mean. It doesn't mean it is clock pin though, And I want to generate between 1.4mhz 1.8mhz with 8 pulse every specific every 0.1sec,generate 8 number of 1.5mhz. Does it possible?

Please be aware that mHz and MHz are very different things. I have no idea what "mhz" represents.

Now, what do you want to do? Doing googling, I think this library is adjustable to me. But have some question How could I select wave form? Just connect to square wave pin is a solution? And want to know in the site's picture (readme)of digital pins(D0 D1 D2...) And is it different sine wave pin 1 and 2?

A TS555 has no problem with those frequencies, it can produce a square wave at up to 2.7 MHz.

Now,I think the oscillator part is ready.

And want to make oscilloscope with arduino. Using 125MHz crystal, does there way to make oscilloscope that can sand data arduino to computer?

What kind of data do you want to send? How often?

Using 125MHz crystal

Which processor will you be using with that crystal? Want to make like this.

Does it imposible to doing this? Cause using FIFO, at arduino analog pin has just 6 pin at Uno. Using 125MHz clock, it seems to have 11pins.and another adc. And I wonder why it connect to arduino pin. Using ADC chip,doesn't it an digital signal?

And want to know about TDA8703s pin 22 and 23 . At TDA8703s datasheet, Do I following at page 14s circut, and attach anoter pin to clock, analog signal and fifo, does it work? Wondering why D0 and D1 pin is not connected in video...

Given the terrible performance of that oscilloscope and the guy's own admission that he doesn't know what's wrong with it, that is a bad example to follow.

I am totally stunned that he got 50MHz signals through all those wires on the breadboard and it works as well as it does. Maybe he knows more than he shows in that video.

D0 and D1 look like they are connected in the video. That's part of the wide bus going to the display. Normally you would not connect anything to those pins as they are the Serial communication to the USB port and used for programming the Uno. You seem to have some other information that's not on the YouTube video.

There's lots of Arduino oscilloscope projects published out there. Keep searching and you'll find one that does what you want.

Could I just using Arduino Due to solve my problem? Cause It has a 84MHz clock. So does it mean not necessary to use DDS and fifo? It seems like I just using ADC, I could make oscillator and oscilloscope that I refer. Does it correct?

The Arduino Due does have a lot of hardware features that would assist your project. However very few of them are used in the standard Arduino libraries. To get the oscilloscope performance up to the million-samples-per-second class you would need to do a lot more than just analogRead().

If you're interested, download the datasheet and learn how to operate the ADC in DMA mode. You can also DMA the DAC. Or search for projects other people have published online. I'm sure there's a few.

The DAC on the Due is rather limited in its voltage output. Before starting with using the Due as an oscillator (signal generator) you should be sure that you can deal with its limited output. So you have to learn about opamps and analog circuitry too.

The Teensy has a better DAC (or two!) and much better library support for the advanced hardware features. For example, look at FrequencyTimer2 library which is included in the TeensyDuino library package. That may solve your oscillator problem right there.

I am unsure to fully understand your project…however, with a DUE, you can output a square wave up to 240 MHz (thanks to the 480 MHz USB OTG HS clock), output sin waves super easily thru the 2 builtin DACs between 0V and 3.3V, or -1.6V and + 1.6V providing you add some opamps for full swing DACs:

An example sketch to output on 1 DAC an ADC sampling at 1 Msps:

I think arduino due is profit. I have no problem of low output cause I am about to use op amp to 32V signal. And teensy duino has low adc sample rate(100 per sec). And I think I have to use adc chip for oscilloscope. But when I see a circuit with arduino, wondering why adc is connected to analog pin Does it has problem to connect digital pin?

More like 100,000 per sec. A bit of tweaking will make it go faster.

I think that video used all the digital pins for the display. All the analog pins on the Uno can also be used as digital pins too.

In this tutorial, the external ADC is a 6-bit precision ADC which has to be connected to 6 digital pins (in fact, analog pins on a UNO can be used as well as digital pins). With a DUE, you have plenty of available digital pins, and IMO the best you can do is to select 6 digital pins or more inside the same PIO (e.g. PIOC) to read them all within a single line of code.

Umm.... I have a queation that select adc's clock. Say Arduino's clock is 84MHz clock and adc has 60MHz, Then it it divided by 12MHz so does it a 12MHz or adc's clock 60MHz? It is easy to think it is 42MHz or 28MHZ that divided simply But this is not that case so I just have this queation. Which one is correct?

And look at TDA8703 datasheet, limitation is 40MHz but why youtube video that I refer use 50MHz clock?

If TDA8703 needs a 40 MHz external clock, you can provide it thru a DUE if you clock this board at 80 Mhz (by selecting the 8 MHz internal RC oscillator instead of the default 12MHz RC oscillator).

TDA8703 do not say anything about the quality of ADC conversions if it is clocked above 40 MHz, hence I suppose it outputs mainly garbage with a 50 or 60 Mhz clock.