Circuit Envelope Simulator Question - RF Cafe Forums
Post subject: Circuit Envelope Simulator Question..
Unread postPosted: Fri May 21, 2004 11:55 am
I use ADS to simulate a PA (modeled by a .p2d file) feedforward
Anyone knows if in circuit envelope simulations the
group delay of the amplifier is actually evaluated?or should i include
it as an external delay element?
tnx in advance :wink:
Sat May 22, 2004 2:35 am
I think you may add the group delay
option in the HB simulation engine. When you simulate a linearizer
you use HB or LSSP engines to view the non-linear S-parameter results.
There should be an option to view the group delay of the circuit
as you do it with linear simulation. I should also check this option
myself. If not, then try to use the S-parameter engine only and
check the group delay option.
BTW Feedforward is not trendy
nowadays, there are Pre-distortion techniques which are more popular.
If you need information I will be keen to help you.
Unread postPosted: Wed May 26, 2004 5:03 am
tnx for the reply.. :)
i need to use envelope simulation to see
the behaviour of the linearizer when fed with complex signals, in
the controller there is no any group delay option. as long as i
remember it is peculiar of s-parameter controller, and is used to
store in a variable called "delay" the group delay calculated from
anyway i am almost sure it is not evaluated
in simulation and so am using an external delay element. if someone
has a final ansewer on the subject i am listening ;-)
Thu May 27, 2004 3:13 pm
Are you using the Ptolmy tool for
envelope simulation or another tool?
You said that you use
an external element for delay, Are you using it as a constant reference
delay at the input and by that derive the the delay that your system
There must be a delay option that as you said
is calculated from the delay of the S-parameters: delta phase/frequency,
and from that the group delay is derived. I used it myself not long
ago to find a group delay of a filter.
Fri May 28, 2004 10:31 am
i am using envelope
inside the RF/Analog simulator, not ptolemy.
a delay element after the amplifier to simulate the effect of the
group delay, because i didn't see the effect of the group delay
on the previous simulations results.
i couldn't find any
option related to group delay in envelope controller, i looked in
the hidden parameters (the ones in the display tab) but found nothing.