Have a question about ADCs or DACs? Ask our Expert, Nick Gray

HI !

I  PUSH  "LOGIN"  IN  YOUR  POST   NOTHING  NO  HAPPEN ......IN  YOUR   POST.

ATTEMPT   SEND   QUESTION  FOR   NICK  GRAY  CALL    DEMAND  TO   INCLUDE   PEOPLE   FROM

LIST...?

ALL   TANGLED  AND  COMPLICATED  OR   I   SOMETHIING   NO  UNDERSTAND.

REGARDS

VIANTRO22

Hello Viktor,

I do see your question about trying to login. All you need to do to ask a question is to do whatever you did to ask about logging in. I look forward to answering your question once you post it.

- Nick Gray

HI  NICK !

I  WRITED  IN  YOUR  BLOG  and  email  YESTERDAY.

OK !  I  REPEAT.

I  DESIGNED  ADCs   with  function  amplitude  detector.

THESE   ADCs  no  require  sample-hold  swich  and  anti-aliasing  filter.

INPUT  SIGNAL   for  ADCs  is  RF ,  OUTPUT  SIGNAL  frequency  amplitude modulation.

THESE   ADCs   may  be  to  apply  for  direct  conversion  receivers,power  meters, adaptive  signal  processing  chips.....

I  WILL   WANT  TO  SEE   these  ADCs  as  high  tecnologic  products

YOUR   OPINION  about  necessity   ADCs  with  function  AD   today  ?

HI  NICK !

I  WRITED  IN  YOUR  BLOG  and  email  YESTERDAY.

OK !  I  REPEAT.

I  DESIGNED  ADCs   with  function  amplitude  detector.

THESE   ADCs  no  require  sample-hold  swich  and  anti-aliasing  filter.

INPUT  SIGNAL   for  ADCs  is  RF ,  OUTPUT  SIGNAL  frequency  amplitude modulation.

THESE   ADCs   may  be  to  apply  for  direct  conversion  receivers,power  meters, adaptive  signal  processing  chips.....

I  WILL   WANT  TO  SEE   these  ADCs  as  high  tecnologic  products

YOUR   OPINION  about  necessity   ADCs  with  function  AD   today  ?

Hi Viktor,

I am sorry, but I am not at all sure just what this ADC is because you say the input is RF and the output is "frequency amplitude modulation". Are you doing both FM and AM, or what? You also say that this could be used for direct conversion receivers, which DEmodulate or detect, not modulate. I am sorry, but I am totally confused as to what your ADC does or how it may do it.

As for amplitude detection, that is a rather simple thing to do and is already being done. Refer to National Semiconductor's ADC121C021, which has VMIN and VMAX registgers that hold the lowest and highest conversion results, which is effectively an amplitude detector.

My opinino about the "necessity" of this function is that it could be very helpful for some applications, but an ADC that has this single function only would have very limited use. Other functions would have to be provided to make the product useful, as is done with the ADC121C021.

- Nick Gray

2011/2/21 Nicholas Gray <messages@element14.com>

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Have a question about ADCs or DACs? Ask our Expert, Nick Gray created by

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HI   NICK!

NICK, ISEND  SHEMES   AND  DIAGRAMs  of  work   ADCs

I  WAIT  ANSWER.

MY  REGARDS

VIKTOR  TROITSKIY

Hi Viktor,

What you have designed is a tracking ADC (see http://www.opamp-electronics.com/tutorials/digital_theory_ch_013.htm just a little lower than half way down the page) that captures the peaks. The use of such a device would be a combination of digitization and AM demodulation. This does pretty much what a high speed converter does in the undersampling mode, so I do not see how it offers anything new. The difficulty here I see is that the clock rate must be the same as the AM carrier rate, which can be quite fast. Undersampling converters use clock rates much lower than the incoming carrier rate to do the same thing. So, I hate to say this, but I see no advantage to your design.

- Nick Gray

2011/2/27 Nicholas Gray <messages@element14.com>

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Have a question about ADCs or DACs? Ask our Expert, Nick Gray created by

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Attachments:

I see your latest figure, but you did not say anything about it. This figure does not change my thoughts on the circuit.

- Nick Gray

HI  NICK!

I  SEND  SHEET  WITH  COMMENTS ,REALLY  FIGURE  WITHOUT   COMMENTS ?

NICK  SAY  ME, IN  POST   FROM  21.02 2011  NOT  COMMENT  TOO?

MAY  BE  IT  IS  BECAUSE, I  SEND  POSTS  FROM  gmail

VIKTOR   TROITSKIY

2011/2/27 viktor troitskiy <viantro2255@gmail.com>

>

2011/2/27 Nicholas Gray <messages@element14.com>

 

>>       image: element14<http://www.element-14.com/?CMP=e14notificationemail_header> Re:

>> Have a question about ADCs or DACs? Ask our Expert, Nick Gray created by

>> nickgray <http://www.element-14.com/community/people/nickgray> in *

>> Experts* - View the full discussion<http://www.element-14.com/community/message/27508#27508>

HI  NICK!

ADCs  with  fuction  RF(AM) DETECTOR  work  how  ordinary  sinchronous  amplitude  detector  and  create  only  ONE  DIGITIZED  IMAGE  SIGNAL (FIG.3), what essential simplify  filtering  of  signal.

ADCs  with  undersampling mode (FIG.2)  work  how  downconverter  and  create  FEW  IMAGES,  what  oblige  application  complicated  anti-alians filters.

THEREFORE,PRESENCE  ONLY  ONE  DIGITIZED IMAGE (FIG.3) IN  COMPARISON  WITH  FEW  DIGITIZED  IMAGES (FIG.2)  IT  IS  MAIN  ADVANTAGE  ADCs  with  function AM DETECTOR .

CLOCK  RATE  THESE ADCs  DEPEND  FROM ELEMENT  BASE AND  WILL BE  GROW.

NOW  ABOUT  TRACKING  ADCs.IN  YOURS  REFERENCE  NOT  SIMILAR  TRACKING  ADCs.

IN  MY  POST  from  2011/02/21  show  THREE  TYPE  ADCs.

     FIG.1 SHOW  ADC  without  clock  generator  and  with  two  comparators for  input  signal.

     FIG.2 SHOW  ADC  with  clock  generator  and  with  two  comparators  for  input  signal.

     FIG.3 SHOW  HIGH SPEED  ADC  with  CHANGED  STEP  CONVERSION  and  four  comparators for

input  signal.

     INPUT  SIGNAL  FOR  THESE  ADCs   RF/IF  AC  SIGNAL.

     OUTPUT  SIGNAL  amplitude  modulation (AM)  or  envelope  INPUT SIGNAL.

THESE  PROPERTY  NOT  IN YOURS  EXAMPLES,THEREFORE  THAT  TOO  ADVANTAGE  ADCs  WITH  FUNCTION  AMPLITUDE  DETECTOR.

MORE  DETAILED   ABOUT  ADVENTAGES  THESE  ADCs  in  direct  convesion  receivers  DISCUSSION

IT   IS  POSSIBLE.

BEST   REGARDS

VIKTOR   TROITSKIY

Hi Viktor,

I believe that I now understand what you are saying, and it makes sense. I believe the problem will be sampling at the AM carrier rate. Timing will be very critical. If you think that overcoming the problems is practical, then I suggest you should write up your idea to protect a possible patent, then seek our a semiconductor manufacturer that may be interested. However, I suspect that no semiconductor manufacturer would want to buy your idea and develop it, but someone might buy it if it were already developed. It does sound like a good idea, but that it will be difficult to implement.

Good luck and best regards,

- Nick Gray