Welcome to EDAboard.com

Welcome to our site! EDAboard.com is an international Electronic Discussion Forum focused on EDA software, circuits, schematics, books, theory, papers, asic, pld, 8051, DSP, Network, RF, Analog Design, PCB, Service Manuals... and a whole lot more! To participate you need to register. Registration is free. Click here to register now.

tuning range of vco in cosmos scope

Status
Not open for further replies.

Fractional-N

Full Member level 1
Joined
Oct 15, 2007
Messages
97
Helped
2
Reputation
4
Reaction score
2
Trophy points
1,288
Activity points
2,063
look @ this pic

how can I display the tuning range of a ring vco in Cosmos Scope, like this
is there a special command (in hspice or hspicerf) to calculate the frequency
or
is there a special tool in Cosmos Scope to measure the freq of a waveform?
thnx!
 

Hughes

Advanced Member level 3
Joined
Jun 10, 2003
Messages
717
Helped
113
Reputation
226
Reaction score
25
Trophy points
1,298
Activity points
5,986
You can use hspice ".meas" command to calculate the frequency:
Code:
vtune ... ... ...
.option post autostop
.tran 0.01n 100u sweep vtune 0.3 0.8 0.05
.meas tran posc trig v(vco_out) val = 1.25 rise=2
+ targ V(vco_out) val = 1.25 rise=3
.meas tran fosc param='1/posc'
Then plot the file with extension ".mt0", set the x-axis to vtune.

Cosmos scope can also measure the frequency of a wave by measurement tool. You can access this tool by a button at the bottom of the window. Use hspice ".meas" command is better in this case.
 

AdvaRes

Advanced Member level 4
Joined
Feb 14, 2008
Messages
1,166
Helped
113
Reputation
220
Reaction score
50
Trophy points
1,328
Location
At home
Activity points
7,444
Hi all,

I'm doing manually that task using an Excell Spreadsheet. I plotted manually the curve an I found a curve like this. I didn't saw something like that before. Is that kind of curves familiar in VCO ? I need your commments.
 

Fractional-N

Full Member level 1
Joined
Oct 15, 2007
Messages
97
Helped
2
Reputation
4
Reaction score
2
Trophy points
1,288
Activity points
2,063
thnx Hughes you help a lot!

AdvaRes said:
Hi all,

I'm doing manually that task using an Excell Spreadsheet. I plotted manually the curve an I found a curve like this. I didn't saw something like that before. Is that kind of curves familiar in VCO ? I need your commments.

Generally speaking, No, it is not a familiar curve for a VCO, also it is not impossible for a VCO to have a curve like that. let us see your circuit :D
 

Status
Not open for further replies.

Part and Inventory Search

Welcome to EDABoard.com

Sponsor

Top