Automated Amp Freq Response plot question

QA40x
1

I am wondering if I am doing something wrong when doing an automated Amp Freq Response plot on an integrated amp. Here are the settings:
autofrsettings
Here is the plot I got after setting the axes:

automated fr
automated fr1007×714 98.6 KB

I have 2 questions:

  1. Is there a way to label each trace for the different input power levels- it was not apparent to me?
  2. How do you get rid of “Pen not going up” trace is what I would call it. Back in the days of pen plotters like the HP7470A you needed to send a “Pen Up” command to the plotter when you were done plotting a trace…

Thanks,

1 Like
2

Hi @VAR, that’s a bug I just repro’d too.

  1. To label a trace you make the trace you want to change the current trace, and then you do Trace->Rename Trace

  2. Bug as noted above, will fix for next release

3

Thanks Matt. However, It will only let me rename one of the traces, it does not appear to know there are two of them so I cannot differentiate which trace is at which input power level. Is that part of the bug ?

4

@VAR your reference to the HP GL “Pen Up” command made me smile. I knew exactly what you meant. We had a number of HP-7220C in our control systems lab in the early 80s and I remember making that very error - on more than one occasion. Install a new set of pens and a sheet of quality white paper and it was a pleasure to watch it plot.

7220C-37
7220C-37817×620 87.1 KB

5

Yes, that’s part of the bug. The lack of “pen up” that you note is the two traces being merged into one. Hopefully this week the new release posts.

1 Like
6

Thanks Matt. Built my speaker impedance test cables so trying them out is today’s fun…

7

I am glad to know I am not the only guy here who knew what I was talking about. I never had to pleasure of using the 722c, but did use the 6pen 7475a. They were pretty slick- using a static system to hold down the paper. Having the pens run out of ink or get dull was common place. I started out programming with the HP9825 instrument controllers- those were so cool back then.

1 Like
8

Hi @VAR, 0.998 was just posted HERE which should fix this.

image
image834×472 6.86 KB

9

That is good news. Will download and install shortly :grin:

10

Matt- thanks again for the way you support this product, and it has provided me with a lot of enjoyment, and will continue to do so I am sure. I think the main thing that is missing for me, at least, are not having are markers for the EXPO Chirp FR- is that something that is in the works or not that easy to do ?

Scott

11

Hi @VAR,

Yes, the cursor code has been prototyped for the graph tool (see below), and needs to be merged in with a few changes. In short, you will have the ability to turn on Cursor 1 and Cursor 2 independently, drag as needed, and if both are on you will see the delta between C1 and C2 (like most spice programs). I don’t know the exact timeline, but it’s coming.

image
image849×687 7.72 KB

12

That is good news, Matt. The example you show above has just a delta X being shown and no delta Y- I assume there would be both delta X and Y. Also you mention that it is part of the Graph Tool- will we be able to at least set Markers when in the Expo Chirp FR mode ? That would be a nice holiday present :slightly_smiling_face: