Electronic Schematics (alt.binaries.schematics.electronic) A place to show and share your electronics schematic drawings.

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  #71   Report Post  
Old April 19th 15, 01:04 AM posted to sci.electronics.design,alt.binaries.schematics.electronic,sci.electronics.basics
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Posts: 2,181
Default "Random" Circuit Needed.

On Sat, 18 Apr 2015 17:35:20 -0500, John Fields
wrote:

On Fri, 17 Apr 2015 10:43:42 -0700, John Larkin
wrote:

On Thu, 16 Apr 2015 23:14:35 -0500, John Fields
wrote:


[snip]

Some of us have progressed past the soldering iron stage



Now that's really sad. What do you do all day, argue and whine on
newsgroups?


---
Funny you should ask - since you've already made up your mind - but
no; I do heavy-duty innovative circuit design instead of
paint-by-number engineering.


Sno-o-o-ort! :-}

...Jim Thompson
--
| James E.Thompson | mens |
| Analog Innovations | et |
| Analog/Mixed-Signal ASIC's and Discrete Systems | manus |
| San Tan Valley, AZ 85142 Skype: skypeanalog | |
| Voice480)460-2350 Fax: Available upon request | Brass Rat |
| E-mail Icon at http://www.analog-innovations.com | 1962 |

I love to cook with wine. Sometimes I even put it in the food.

  #72   Report Post  
Old April 19th 15, 02:32 AM posted to sci.electronics.design,alt.binaries.schematics.electronic,sci.electronics.basics
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First recorded activity by DIYBanter: Feb 2012
Posts: 231
Default "Random" Circuit Needed.

On Sat, 18 Apr 2015 17:35:20 -0500, John Fields
wrote:

On Fri, 17 Apr 2015 10:43:42 -0700, John Larkin
wrote:

On Thu, 16 Apr 2015 23:14:35 -0500, John Fields
wrote:

On Thu, 16 Apr 2015 10:47:36 -0700, John Larkin
wrote:


These are electronics newsgroups.

---
And, as such, your narcissistic off-topic garbage has no proper
place here.
---

We do seem to have a faction of
ancient cackling farts who only want to gossip and whine about
personalities, and drone out insults, and haven't touched a soldering
iron in years, or decades.

---
Some of us have progressed past the soldering iron stage



Now that's really sad. What do you do all day, argue and whine on
newsgroups?


---
Funny you should ask - since you've already made up your mind - but
no; I do heavy-duty innovative circuit design instead of
paint-by-number engineering.


Cool. Tell us about what you're working on.


--

John Larkin Highland Technology, Inc
picosecond timing laser drivers and controllers

jlarkin att highlandtechnology dott com
http://www.highlandtechnology.com

  #73   Report Post  
Old April 19th 15, 02:42 AM posted to sci.electronics.design,alt.binaries.schematics.electronic,sci.electronics.basics
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First recorded activity by DIYBanter: Jul 2009
Posts: 83
Default "Random" Circuit Needed.

On Sun, 19 Apr 2015 09:00:58 +1000, John Fields
wrote:

On Sat, 18 Apr 2015 22:15:13 +1000, "David Eather"
wrote:

On Sat, 18 Apr 2015 20:30:31 +1000, Jasen Betts
wrote:

On 2015-04-18, rickman wrote:
On 4/17/2015 10:56 PM, Jasen Betts wrote:
On 2015-04-17, rickman wrote:
On 4/17/2015 7:51 AM, Jasen Betts wrote:

one 16 bit - 7 bit subtract
one 16 bit + 0 bit add with carry.

I'm not following. Are you saying a modulo 65537 operation can be
done
with two adders?

yes.

I appreciate the effort in the drawing, but that isn't needed.
Knowing
that you use adders doesn't help me understand how the arithmetic
works.
Is there a simple explanation? BTW, what do you do with bit 16 on
the
input? Is that a typo? Does it go with the lsbs or the msbs?

It's a typo (or a fence-post error).

this is the arithmetic in c:

// a=a % 65537 in c:

a = a & 0xffff - ( a & ~ 0xffff ) 16;
a = a0 ? a & 0xffff + 1 : a ;


Its an abortive mistake.

It should be mod 2^n i.e. 65536. or 256 or 16 etc

also you don't use a rotation just a left shift. Each left shift by 1
bit
works like a multiply *2 and you don't need to track the carry outs or
MSB's of the shifted number the mod function throws them away anyway.

So to use an adder to multiply by say 5 you have the input number feed
into one input of the adder shifted left by 2 bits - that is 4 x the
input
number. Into the other input of the adder you input the original seed -
so
4 x the input number plus the input number = 5 x the input number. If
the
modulus function is a power of 2 then discarding the right number of
MSB's
take care of that - you don't even have to feed them into the adder
since
the result will be discarded anyway.

Last if you use the carry in of the least significant adder as a + 1
function then a simple LCG takes one adder only (excluding latches you
might need to avoid race issues)


---
So you have to use a shifter, adders, latches, and some glue logic
to get to 2^n?


NO shifter, repeat NO shifter, and total glue logic equals 1 inverter.


How is that simpler than using a shifter, a few EXORs and a NOR to
do the same thing?

John Fields


No it does not do the same thing.

I like LFSR but they may not work in the specific case Jim asked for.

A LFSR does not produce all possible output states - it will not produce
all zeros or all ones depending on the configuration. This means that it
may cause the AGC control voltage to drift high or low until it rails.
Which rather wrecks Jim's simulation.

On the other hand and LCG as I described produces every possible state
once per cycle and will not have a potential problem if used to control
and AGC.

Since it is for simulation, the cost of an LCG is not an issue and it only
takes a small time to implement.

QED.
  #74   Report Post  
Old April 19th 15, 03:16 AM posted to sci.electronics.design,alt.binaries.schematics.electronic,sci.electronics.basics
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First recorded activity by DIYBanter: Apr 2015
Posts: 898
Default "Random" Circuit Needed.

On Sat, 18 Apr 2015 17:32:51 -0700, John Larkin
wrote:

On Sat, 18 Apr 2015 17:35:20 -0500, John Fields
wrote:

On Fri, 17 Apr 2015 10:43:42 -0700, John Larkin
wrote:

On Thu, 16 Apr 2015 23:14:35 -0500, John Fields
wrote:

On Thu, 16 Apr 2015 10:47:36 -0700, John Larkin
wrote:


These are electronics newsgroups.

---
And, as such, your narcissistic off-topic garbage has no proper
place here.
---

We do seem to have a faction of
ancient cackling farts who only want to gossip and whine about
personalities, and drone out insults, and haven't touched a soldering
iron in years, or decades.

---
Some of us have progressed past the soldering iron stage


Now that's really sad. What do you do all day, argue and whine on
newsgroups?


---
Funny you should ask - since you've already made up your mind - but
no; I do heavy-duty innovative circuit design instead of
paint-by-number engineering.


Cool. Tell us about what you're working on.


A new 555 circuit.
  #75   Report Post  
Old April 19th 15, 03:29 AM posted to sci.electronics.design,alt.binaries.schematics.electronic,sci.electronics.basics
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First recorded activity by DIYBanter: Feb 2012
Posts: 231
Default "Random" Circuit Needed.

On Sat, 18 Apr 2015 21:16:52 -0400, krw wrote:

On Sat, 18 Apr 2015 17:32:51 -0700, John Larkin
wrote:

On Sat, 18 Apr 2015 17:35:20 -0500, John Fields
wrote:

On Fri, 17 Apr 2015 10:43:42 -0700, John Larkin
wrote:

On Thu, 16 Apr 2015 23:14:35 -0500, John Fields
wrote:

On Thu, 16 Apr 2015 10:47:36 -0700, John Larkin
wrote:


These are electronics newsgroups.

---
And, as such, your narcissistic off-topic garbage has no proper
place here.
---

We do seem to have a faction of
ancient cackling farts who only want to gossip and whine about
personalities, and drone out insults, and haven't touched a soldering
iron in years, or decades.

---
Some of us have progressed past the soldering iron stage


Now that's really sad. What do you do all day, argue and whine on
newsgroups?

---
Funny you should ask - since you've already made up your mind - but
no; I do heavy-duty innovative circuit design instead of
paint-by-number engineering.


Cool. Tell us about what you're working on.


A new 555 circuit.


Is that possible?


--

John Larkin Highland Technology, Inc
picosecond timing laser drivers and controllers

jlarkin att highlandtechnology dott com
http://www.highlandtechnology.com



  #76   Report Post  
Old April 19th 15, 05:14 AM posted to sci.electronics.design,alt.binaries.schematics.electronic,sci.electronics.basics
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First recorded activity by DIYBanter: Jul 2008
Posts: 329
Default "Random" Circuit Needed.

On 2015-04-18, David Eather wrote:
On Thu, 02 Apr 2015 20:42:50 +1000, Jasen Betts wrote:


I was wondering about that myself... I'll see if there's a cure.


r=(75*r+74)%65537 visits 0-65535 with no gaps.

not that i'd want to build it using 74LS logic.


That is an absolute turd. It screws up if the cycle tries to repeat more
than once - it not longer visits 0 - 65535 without gaps (it outputs a
665536 which needs 17 bits) and will miss a 16 bit number every cycle
after the first, OR if the 17-th bit is ignored it will produce an excess
number of zeros.


No, that is absolute bull****.

it's this:
http://en.wikipedia.org/wiki/Lehmer_...mber_generator

except offset by -1 so that the Lehmer zero state (which is
disallowed) is excluded and the maximal state fits in 16 bits.

--
umop apisdn

  #77   Report Post  
Old April 19th 15, 05:36 AM posted to sci.electronics.design,alt.binaries.schematics.electronic,sci.electronics.basics
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First recorded activity by DIYBanter: Jul 2008
Posts: 329
Default "Random" Circuit Needed.

On 2015-04-18, rickman wrote:
On 4/18/2015 6:30 AM, Jasen Betts wrote:
On 2015-04-18, rickman wrote:
On 4/17/2015 10:56 PM, Jasen Betts wrote:
On 2015-04-17, rickman wrote:
On 4/17/2015 7:51 AM, Jasen Betts wrote:

one 16 bit - 7 bit subtract
one 16 bit + 0 bit add with carry.

I'm not following. Are you saying a modulo 65537 operation can be done
with two adders?

yes.


I appreciate the effort in the drawing, but that isn't needed. Knowing
that you use adders doesn't help me understand how the arithmetic works.
Is there a simple explanation? BTW, what do you do with bit 16 on the
input? Is that a typo? Does it go with the lsbs or the msbs?


It's a typo (or a fence-post error).

this is the arithmetic in c:

// a=a % 65537 in c:

a = a & 0xffff - ( a & ~ 0xffff ) 16;
a = a0 ? a & 0xffff + 1 : a ;


I don't need an algebraic formula to understand the logic. I am asking
how this is equivalent to mod 65537. But running through a couple of
examples I think I understand. It does a division by 65536 and adjusts
the remainder with the quotient and an additional adjustment if the
result is negative. Interesting and fairly efficient. Where did you
learn about this?


I discovered it when I was ih highschool, it's not that different to
the trick to compute y=x%11 in base 10 only it's done in base 65536
and only does two digits.

--
umop apisdn

  #78   Report Post  
Old April 19th 15, 06:00 AM posted to sci.electronics.design,alt.binaries.schematics.electronic,sci.electronics.basics
external usenet poster
 
First recorded activity by DIYBanter: Apr 2015
Posts: 898
Default "Random" Circuit Needed.

On Sat, 18 Apr 2015 18:29:50 -0700, John Larkin
wrote:

On Sat, 18 Apr 2015 21:16:52 -0400, krw wrote:

On Sat, 18 Apr 2015 17:32:51 -0700, John Larkin
wrote:

On Sat, 18 Apr 2015 17:35:20 -0500, John Fields
wrote:

On Fri, 17 Apr 2015 10:43:42 -0700, John Larkin
wrote:

On Thu, 16 Apr 2015 23:14:35 -0500, John Fields
wrote:

On Thu, 16 Apr 2015 10:47:36 -0700, John Larkin
wrote:


These are electronics newsgroups.

---
And, as such, your narcissistic off-topic garbage has no proper
place here.
---

We do seem to have a faction of
ancient cackling farts who only want to gossip and whine about
personalities, and drone out insults, and haven't touched a soldering
iron in years, or decades.

---
Some of us have progressed past the soldering iron stage


Now that's really sad. What do you do all day, argue and whine on
newsgroups?

---
Funny you should ask - since you've already made up your mind - but
no; I do heavy-duty innovative circuit design instead of
paint-by-number engineering.

Cool. Tell us about what you're working on.


A new 555 circuit.


Is that possible?


That's why the job is so heavy duty.
  #79   Report Post  
Old April 19th 15, 08:53 AM posted to sci.electronics.design,alt.binaries.schematics.electronic,sci.electronics.basics
external usenet poster
 
First recorded activity by DIYBanter: Jul 2006
Posts: 2,022
Default "Random" Circuit Needed.

On Sat, 18 Apr 2015 17:32:51 -0700, John Larkin
wrote:

On Sat, 18 Apr 2015 17:35:20 -0500, John Fields
wrote:

On Fri, 17 Apr 2015 10:43:42 -0700, John Larkin
wrote:

On Thu, 16 Apr 2015 23:14:35 -0500, John Fields
wrote:

On Thu, 16 Apr 2015 10:47:36 -0700, John Larkin
wrote:


These are electronics newsgroups.

---
And, as such, your narcissistic off-topic garbage has no proper
place here.
---

We do seem to have a faction of
ancient cackling farts who only want to gossip and whine about
personalities, and drone out insults, and haven't touched a soldering
iron in years, or decades.

---
Some of us have progressed past the soldering iron stage


Now that's really sad. What do you do all day, argue and whine on
newsgroups?


---
Funny you should ask - since you've already made up your mind - but
no; I do heavy-duty innovative circuit design instead of
paint-by-number engineering.


Cool. Tell us about what you're working on.


---
Sorry, loose lips sink ships...

John Fields
  #80   Report Post  
Old April 19th 15, 09:03 AM posted to sci.electronics.design,alt.binaries.schematics.electronic,sci.electronics.basics
external usenet poster
 
First recorded activity by DIYBanter: Jul 2006
Posts: 2,022
Default "Random" Circuit Needed.

On Sat, 18 Apr 2015 21:16:52 -0400, krw wrote:

On Sat, 18 Apr 2015 17:32:51 -0700, John Larkin
wrote:

On Sat, 18 Apr 2015 17:35:20 -0500, John Fields
wrote:

On Fri, 17 Apr 2015 10:43:42 -0700, John Larkin
wrote:

On Thu, 16 Apr 2015 23:14:35 -0500, John Fields
wrote:

On Thu, 16 Apr 2015 10:47:36 -0700, John Larkin
wrote:


These are electronics newsgroups.

---
And, as such, your narcissistic off-topic garbage has no proper
place here.
---

We do seem to have a faction of
ancient cackling farts who only want to gossip and whine about
personalities, and drone out insults, and haven't touched a soldering
iron in years, or decades.

---
Some of us have progressed past the soldering iron stage


Now that's really sad. What do you do all day, argue and whine on
newsgroups?

---
Funny you should ask - since you've already made up your mind - but
no; I do heavy-duty innovative circuit design instead of
paint-by-number engineering.


Cool. Tell us about what you're working on.


A new 555 circuit.


---
And what, exactly, would be wrong with that?



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