Welcome to EDAboard.com

Welcome to our site! EDAboard.com is an international Electronics 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.

IIP3 @ 10MHz offset for WCDMA

Status
Not open for further replies.

boshiouke

Junior Member level 3
Joined
Aug 11, 2005
Messages
25
Helped
1
Reputation
2
Reaction score
1
Trophy points
1,283
Activity points
1,528
The inband IIP3 for WCDMA is specified @ 10MHz offset. So I ran a 2-tone test w/ following parameters,

RF1=2150MHz
RF2=2160MHz
LO=2140MHz

First of all, should I have used the 2 tones @ 10/20.5MHz so that IM3(0.5MHz) falls within the BW(5MHz)?

Secondly, due the LPF @ mixer output w/ cutoff of 8MHz, the output @ 10MHz is much bigger than @ 20MHz. In this case, how do I calculate IIP3? Does "Pin+1/2 x (delta between fundamental and IM3)" still apply? Which 2 frequencies should I take the delta from? Assuming the Pin is in linear region of the mixer.

Thank you so much.
 

vfone

Advanced Member level 5
Joined
Oct 10, 2001
Messages
5,392
Helped
1,560
Reputation
3,123
Reaction score
1,170
Trophy points
1,393
Activity points
34,178
Receiver IIP3 is:
IIP3(dBm) = 2tone_lev(dBm) + [2tone_lev(dBm) – RX_lev(dBm) + S/N(dB) ] / 2
where:
2tone_lev = Two-tone intermodulation level in dBm (WCDMA spec requirement is –46dBm @ +/-10MHz and +/-20MHz from the receive frequency)
RX_lev = Receiver desired input level (RX sensitivity + 3dB)
S/N = Analog Signal to Noise Ratio (~9dB)
 

boshiouke

Junior Member level 3
Joined
Aug 11, 2005
Messages
25
Helped
1
Reputation
2
Reaction score
1
Trophy points
1,283
Activity points
1,528
I appreciate your input, Vfone. But I'm aware of the info you posted from a WCDMA system article from Microwave Journal. What I want to know is how to relate that to the numbers I have, as indicated in my posting. Thank you.
 

vfone

Advanced Member level 5
Joined
Oct 10, 2001
Messages
5,392
Helped
1,560
Reputation
3,123
Reaction score
1,170
Trophy points
1,393
Activity points
34,178
First of all I don’t know what MWJ article you are talking about. This is a standard RF systems formula.
Second, you have to follow the WCDMA spec for levels, spacing, etc.
Third, seems that you are looking to calculate the LNA IIP3 not Receiver IIP3. They are different things.
 

boshiouke

Junior Member level 3
Joined
Aug 11, 2005
Messages
25
Helped
1
Reputation
2
Reaction score
1
Trophy points
1,283
Activity points
1,528
Again, I appreciate your attention, Vfone. Here's the link to the article I was talking about.
http://www.mwjournal.com/default.as...ion=1&section=2&maxres=25&SearchSubmit=Search

If the link doesn't work, simply go to www.mwjournal.com and search for w-cdma in Feb. 2000 issue. It talks about how to derive IP3 for the ENTIRE Rx, not only mixer.

But, what I'm asking is for mixer ONLY, specifically during simulation of a 2-tone test. As indicated in Razavi's book, I do know the "quick way" to calculate IIP3. But my case is kind of different.

Thank you.
 

Status
Not open for further replies.

Similar threads

Part and Inventory Search

Welcome to EDABoard.com

Sponsor

Top