Still waiting for a Ltspice expert answer.

Please, pretty please, don' open that can of worms again. It was talked to death some time ago ;-)

--
"For a successful technology, reality must take precedence 
over public relations, for nature cannot be fooled."
                                       (Richard Feynman)

[smirk] ...Jim Thompson

-- | James E.Thompson, CTO | mens | | Analog Innovations, Inc. | et | | Analog/Mixed-Signal ASIC's and Discrete Systems | manus | | Phoenix, Arizona 85048 Skype: Contacts Only | | | Voice:(480)460-2350 Fax: Available upon request | Brass Rat | | E-mail Icon at

| 1962 | I love to cook with wine. Sometimes I even put it in the food.

The model is the RLCG model for transmission lines.

R = resistance L = inductance C = capacitance G = conductance

The R and L are in series with the line. The c and G are in parallel. These parameters are on a per-meter basis, multiply by the length dz to obtain the total element value in ohms, henries, farads and siemens.

Look at Gayle Miner's book: Lines and Electromagnetic Fields for Engineers. p10-14

HTH, Dave

Most, if not all Spice do not fully implement an RLCG model. The lossy line model, LTRA, only implements R, L, and C. Nonzero G not supported (yet).

The parameters are on a *per-unit* basis, not per-meter, allowing the use of feet, inches, millimeters, cubits, parsecs, whatever.

Examples:

.model RG223 LTRA (LEN=1 R=11.3m L=0.077u C=30.8p)

.model RG59 LTRA (LEN=1 R=51.6m L=0.115u C=20.5p)

Units in this case are per foot.

--
"For a successful technology, reality must take precedence 
over public relations, for nature cannot be fooled."
                                       (Richard Feynman)

PSpice has a full RLCG model... "TLOSSY" in the parts index. ...Jim Thompson

--
| James E.Thompson, CTO                            |    mens     |
| Analog Innovations, Inc.                         |     et      |
| Analog/Mixed-Signal ASIC's and Discrete Systems  |    manus    |
| Phoenix, Arizona  85048    Skype: Contacts Only  |             |
| Voice:(480)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.

Didn't know that. LTspice *appears* to have, then you try to use G, and it tells you to go away.

It appears to be code lifted straight out of Berkeley Spice 3.

--
"For a successful technology, reality must take precedence 
over public relations, for nature cannot be fooled."
                                       (Richard Feynman)

On Jan 25, 4:15=A0pm, Jim Thompson wrote: ...snip...

..snip...

=A0 =A0 ...Jim Thompson

=A0 =A0| =A0 =A0mens =A0 =A0 |

=A0 | =A0 =A0 et =A0 =A0 =A0|

=A0|

=A0 =A0 =A0 |

Glad you added "test equipment" Too often THAT is trusted more than it warrants!

I embarrassingly once spent 4 hours tracking down, yes, test equipment problem, not a circuit problem! Learned a healthy respect to distrust EVERYTHING, That even includes distrusting the values marked on the components when you breadboard - especially after using 10 ohm resistors marked as 1k And, worst of all? a bad lot of IC's! It is surprising how much one blindly trusts incoming parts more than they trust their own designs to work properly. Now I don't even trust data sheets to accurately describe a component. Once, Intel's spec sheet was so wrong that my software group worked 6 weeks trying to 'fix' their software, all wasted time, all caused by an error in Intel's data sheet! When confronted, Intel's response was, oh, yes, that is an error. Thanks a lot for the heads up!

All of the above experiences really describe why one should NEVER trust a 'garage' design. You know, the design works, so build more just like it and start shipping.

After the above experiences, I now trust well worded Buying Contracts, and well documented designs with verification testing using test equipment traceable to the N??? standards. Now, when you do that; THERE is recourse if something doesn't work right.

[snip] [snip]

Not original with me, I was just quoting qrk's comments to try to pound some sense into Jamie... alas, a lost cause... dumb as a stump and twice as thick >:-} ...Jim Thompson

--
| James E.Thompson, CTO                            |    mens     |
| Analog Innovations, Inc.                         |     et      |
| Analog/Mixed-Signal ASIC's and Discrete Systems  |    manus    |
| Phoenix, Arizona  85048    Skype: Contacts Only  |             |
| Voice:(480)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.

I wonder if his employer knows how he looks online. He has mentioned the company, and it only takes a few seconds to find his public records. Even a typical low level NDA signed at the time of employment would be enough legal reason to fire him.

--
You can't have a sense of humor, if you have no sense.

More than once I was called from my bench to see what was wrong on a test setup, to find the problem in seconds becasue the tech didn't follow the procedure to verify the test setup was working. Things like not bothering to zero the offset voltage on a function generator, then failing boards becasue the 'video' output was against one rail. It would piss me off, because I had taught them the proper procedure, before giving them the product to work on.

--
You can't have a sense of humor, if you have no sense.