> > > > Folks, This is a question about applications of technology rather than how to design it.

the classic application would be a PLL

m

On Monday, June 19, 2017 at 6:41:55 PM UTC+1, gyans...@gmail.com wrote:
> On Monday, June 19, 2017 at 9:39:59 PM UTC+12, Steve M wrote:
> > On Wednesday, June 14, 2017 at 3:37:52 PM UTC+1, Steve M wrote:
> > > Folks, This is a question about applications of technology rather than how to design it.
> > > An existing application includes an ADC/floating-point processor/DAC controller to provide a closed-loop solution for emulating physical circuit characteristics up to say 100KHz. The closed-loop controller was required to have an effectively negligible delay (say 200ns) up to at least that frequency.
> > > A research version in progress, for creating say a transmission line input impedance and propagation characteristic requires not only a much greater capability to generate the irrational impedance and propagation transfer function characteristics, but also needs, for at least one application to have a closed-loop controller with an effectively negligible delay (say 20ns) at 1MHz.
> > > So, the question is, are there other applications that require this sort of performance ? or are there applications that need even higher performance ?
> > 
> > After a bit of research (Googling), and questions on Forums, I have concluded :-
> > a) Low-Latency digital controllers < 100ns are out of the mainstream of feedback controller designs.
> > b) Applications are rather niche but do appear in the fields of physics experimentation, MEMs systems, Electrical circuit emulation and other fast all- electronic applications such as SMPS.
> > 
> > It looks like this is an interesting area for research, even if current applications are few and far between.
> 
> Not sure what you mean by low latency. Do you mean high bandwidth controllers? If so hard disk drives of course are well up there for electro-mechanical systems. The think that limits bandwidth is the structural resonance.

Hi gyans, thank you for those observations. I found an example of the sort of application I was thinking of here https://arxiv.org/pdf/1508.06319.pdf where it describes "The servo is capable of feedback bandwidths up to roughly 1 MHz
(limited by the 320 ns total latency);"

On Monday, June 19, 2017 at 9:39:59 PM UTC+12, Steve M wrote:
> On Wednesday, June 14, 2017 at 3:37:52 PM UTC+1, Steve M wrote:
> > Folks, This is a question about applications of technology rather than how to design it.
> > An existing application includes an ADC/floating-point processor/DAC controller to provide a closed-loop solution for emulating physical circuit characteristics up to say 100KHz. The closed-loop controller was required to have an effectively negligible delay (say 200ns) up to at least that frequency.
> > A research version in progress, for creating say a transmission line input impedance and propagation characteristic requires not only a much greater capability to generate the irrational impedance and propagation transfer function characteristics, but also needs, for at least one application to have a closed-loop controller with an effectively negligible delay (say 20ns) at 1MHz.
> > So, the question is, are there other applications that require this sort of performance ? or are there applications that need even higher performance ?
> 
> After a bit of research (Googling), and questions on Forums, I have concluded :-
> a) Low-Latency digital controllers < 100ns are out of the mainstream of feedback controller designs.
> b) Applications are rather niche but do appear in the fields of physics experimentation, MEMs systems, Electrical circuit emulation and other fast all- electronic applications such as SMPS.
> 
> It looks like this is an interesting area for research, even if current applications are few and far between.

Not sure what you mean by low latency. Do you mean high bandwidth controllers? If so hard disk drives of course are well up there for electro-mechanical systems. The think that limits bandwidth is the structural resonance.

On Wednesday, June 14, 2017 at 3:37:52 PM UTC+1, Steve M wrote:
> Folks, This is a question about applications of technology rather than how to design it.
> An existing application includes an ADC/floating-point processor/DAC controller to provide a closed-loop solution for emulating physical circuit characteristics up to say 100KHz. The closed-loop controller was required to have an effectively negligible delay (say 200ns) up to at least that frequency.
> A research version in progress, for creating say a transmission line input impedance and propagation characteristic requires not only a much greater capability to generate the irrational impedance and propagation transfer function characteristics, but also needs, for at least one application to have a closed-loop controller with an effectively negligible delay (say 20ns) at 1MHz.
> So, the question is, are there other applications that require this sort of performance ? or are there applications that need even higher performance ?

After a bit of research (Googling), and questions on Forums, I have concluded :-
a) Low-Latency digital controllers < 100ns are out of the mainstream of feedback controller designs.
b) Applications are rather niche but do appear in the fields of physics experimentation, MEMs systems, Electrical circuit emulation and other fast all- electronic applications such as SMPS.

It looks like this is an interesting area for research, even if current applications are few and far between.

On Thursday, June 15, 2017 at 5:18:37 AM UTC+1, Tim Wescott wrote:
> On Wed, 14 Jun 2017 07:37:46 -0700, Steve M wrote:
> 
> > Folks, This is a question about applications of technology rather than
> > how to design it.
> > An existing application includes an ADC/floating-point processor/DAC
> > controller to provide a closed-loop solution for emulating physical
> > circuit characteristics up to say 100KHz. The closed-loop controller was
> > required to have an effectively negligible delay (say 200ns) up to at
> > least that frequency.
> > A research version in progress, for creating say a transmission line
> > input impedance and propagation characteristic requires not only a much
> > greater capability to generate the irrational impedance and propagation
> > transfer function characteristics, but also needs, for at least one
> > application to have a closed-loop controller with an effectively
> > negligible delay (say 20ns) at 1MHz.
> > So, the question is, are there other applications that require this sort
> > of performance ? or are there applications that need even higher
> > performance ?
> 
> Just look for applications that use fast op-amps now, and ask if they can 
> be made better with digital control.
> 
> Switching power supplies come to mind.
> 
> -- 
> 
> Tim Wescott
> Wescott Design Services
> http://www.wescottdesign.com

Hi Tim, Thanks for the suggestion. I also had that one from one of the SMPS Device manufactures, so it all adds weight.

On Wed, 14 Jun 2017 07:37:46 -0700, Steve M wrote:

> Folks, This is a question about applications of technology rather than
> how to design it.
> An existing application includes an ADC/floating-point processor/DAC
> controller to provide a closed-loop solution for emulating physical
> circuit characteristics up to say 100KHz. The closed-loop controller was
> required to have an effectively negligible delay (say 200ns) up to at
> least that frequency.
> A research version in progress, for creating say a transmission line
> input impedance and propagation characteristic requires not only a much
> greater capability to generate the irrational impedance and propagation
> transfer function characteristics, but also needs, for at least one
> application to have a closed-loop controller with an effectively
> negligible delay (say 20ns) at 1MHz.
> So, the question is, are there other applications that require this sort
> of performance ? or are there applications that need even higher
> performance ?

Just look for applications that use fast op-amps now, and ask if they can 
be made better with digital control.

Switching power supplies come to mind.

-- 

Tim Wescott
Wescott Design Services
http://www.wescottdesign.com

Folks, This is a question about applications of technology rather than how to design it.
An existing application includes an ADC/floating-point processor/DAC controller to provide a closed-loop solution for emulating physical circuit characteristics up to say 100KHz. The closed-loop controller was required to have an effectively negligible delay (say 200ns) up to at least that frequency.
A research version in progress, for creating say a transmission line input impedance and propagation characteristic requires not only a much greater capability to generate the irrational impedance and propagation transfer function characteristics, but also needs, for at least one application to have a closed-loop controller with an effectively negligible delay (say 20ns) at 1MHz.
So, the question is, are there other applications that require this sort of performance ? or are there applications that need even higher performance ?