Search for DDS chip - Page 1
Forum section: electronics / projects

author: IIII
author_rank: Newbie
timestamp: January 13, 2012, 04:21:33 pm
content: Dear all,To drive a PZT for a Research application, I want to make arbitrary signal generators that follow the following characteristics:- Frequency Domain : RF :200MHz- Bandwith :10 MHz- Sample Rate:> = 1GS / s(it's easier for filtering output aliases).- Frequency resolution:48 bits, very important.- Amplitude resolution:14 bit, or less but I may be embarrassed by the quantization noise- Number of channels:2, preferably to facilitate the pcb- Factor(x20, x40)in the PLL from the external clock to facilitate the generation of the ~ 1GHz internal clockSo I am looking for a complete DDS chip for the arbitrary waveform generation. I don't know the manufacturer for the DDS chips, and the chips I've found among the "generic" manufacturer (AD, TI, Maxim, and others) do not meet specifications (such as the AD9912 which generates just RF signals, or the AD9910 which frequency is encode in 32 bits).The classical assemblers of arbitrary waveform generators (Agilent, Tektro) largely meet these specifications. But I don't have such generator on hand to open them and to find the information.So do you know the manufacturers of these DDS chips ?Do you suggest a specific model for my characterics ?Thanks in advance.And Happy New Year to the forum !Max.

author: Zad
author_rank: Super Contributor
timestamp: January 13, 2012, 04:54:24 pm
content: There are two options:1. Analog Devices2. Make your own with an FPGA and DAC.Do you mean data rate or sampling rate? The two are very different. I don't think there are any DDSs which are capable of that update rate. Given the stringent specifications, I suspect FPGA+DAC is going to be the only way forward. Why does it have to have 2 channels, can't you just have two DDSs on the same PCB? 1GHz clock sources aren't difficult to find, so don't worry too much about having an appropriate PLL onboard, in fact for a clean output you ideally don't want to PLL it up anyway.I would get an AD9912 dev board and take it from there. If you absolutely have to have performance down to DC, then design your own output filtering and buffering. It isn't rocket science.

author: Unknown
author_rank: Unknown
timestamp: January 13, 2012, 05:28:41 pm
content: Quote from: IIII on January 13, 2012, 04:21:33 pmSome of them use custom silicon, others will contain DDS generators built from 'discrete' components (eg. FPGA, DAC, memory, filtering). Not sure if you can even find a DAC that meets you requirements, most DACs with a sampling rate of around 1 GS/s are aimed at RF. I wonder what their effective number of bits is at 1 GS/s.Quote from: IIII on January 13, 2012, 04:21:33 pmBuying one from Tek or Agilent will probably be cheaper and have better performance, especially if you factor in labor. Based on your questions, you seem to expect a plug and play solution that will give you an Agilent/Tek-class waveform generator for a fraction of the price.

author: ejeffrey
author_rank: Super Contributor
timestamp: January 13, 2012, 05:39:09 pm
content: The Martinis group at UCSB has some published plans for these. Go to:http://web.physics.ucsb.edu/~martinisgroup/electronics.shtmland follow the link for their wiki login and look at the GHz DAC stuff.

author: Mechatrommer
author_rank: Super Contributor
timestamp: January 13, 2012, 08:53:51 pm
content: 1GS/s? hehehe, you missed another important spec... price. whats your budget?

author: IIII
author_rank: Newbie
timestamp: January 16, 2012, 10:20:33 am
content: Thanks you all for your posts,Quote from: Zad on January 13, 2012, 04:54:24 pmOups, thanks, it's my fault, I was so careful not to make too many mistakes in english that I didn't see this one ! I have modified my first post. Indeed, it is a sample rate of 1GS/s.QuoteI have just received the AD9912 Eval Board and I will test it soon.QuoteFor a complete DDS, the AD9910 seems to work well, but a frequency tuning in 32 bits.To clarify my need for my set-up, the main frequency domain for the signals are RF (200MHz with a bandwith of 10MHz).For the other components of the signal, I can generate it without difficulty by another way. So I need a DDS for RF domain (200MHz +/- 5MHz). I have modified the first post.QuoteThat's the question. I need this RF signals for many set-up. If I have to build about 10 DDS, it will be probably cheaper than buying them. I just want to quantify it (with obviously the time to do it).Thanks for your help.Max