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1000 Threads found on Compression Point
Have a look at my compression point tutorial at :- hope this helps :)
I am using Spectre RF for a mixer design. When I use a two tone test to get the IP2 (using swept qpss) I usually get a very large difference between the 1dB compression point and the IP3. According to theory, IP3=P1dB+9.6 dB However I get difference as large as 16 or 18 dB, what can be the problem? Thanks in advance
An very senior Engineer (20 years in RF design)told me the mixer compression point often 10dB below LO power, so the higher the LO power the higher mixer compressin point. I am wondering what I realize before is the LO power is prohibited to be too high due to harmonics, this also causes mixer linearity degraded. I guess his experience may (...)
Hi All, how to calculate Pin and Pout in dBm? how to determine 1dB compression point from Pin and Pout? How to convert 1dB to dBm? Thanks for your kindly reply. regards, Chun Lee
I am working on the buffer operation @ 2.5GHz and 5GHz. The 1dB compression point is 10dBm. I tried to increase overdrive voltage or gm to improve the P1dB, however, it stops at 8dBm. I do not know how to improve it. Any one can give me some idea. Right now, i am using cascode topology, loading a inductor. Is there any other topology has better lin
I don't know if this is feasible for you but, on the last stage you can send the Input signal thru a Hybrid coupler (90°) and put 2 Output stages in parallel. This will make the -1dB point ~ 3dB higher. Note one of the O/P stages will be terminated to 50 Ohms and so will the unused Input of the Coupler! And one other thing you might look a
i am design a LNA with ADS. While simulating, i find that the output 1dB compression point drops from 12dBm to about 8.5dBm after i substituting the ideal lumped inductor with the real spiral inductor provided by the design kits. it frustrates me. my lna topology is below. anyone knows how to cancel the nonlinearity caused by the nonlinearity of
Hi people Anyone knows how I could design IIP3 and 1dB compression point in a mixer considering volterra and variant system? Best Regards Paulo
I used PSS to simulate the opamp's 1dB compression point in SPECTRL, I found that the output signal swing is higher than vdd at the gain decreased by 1 dB comparing with small signal gain. The result puzzled me. The output voltage is distorted in large signal input. And the input signal must be large enough to make the gain decrease 1dB and now th
Hi,friends, my 1dB compression point is -39dBm, Does anybody can show me a solution to enhance it, thank you
Please share a Hspice code to find the 1 db compression point, IP2 for the gilbert cell using .HB code. Thank you very much.
hi guys, i got 2 graph of simulated results. both with 1db compression and IIP3 result. while the difference is one with lower 1db compression point but higher IIp3 point than the others. Is that normal???
Hi there, why does only two harmonics are required to determine the 1dB compression point?
Hi, i want to learn about 3rd-Order compression point (IP3) & RF amplifiers in general ,Im a beginner in RF field..Can somebody recommend me some good books to start with?? Thanks n Regards
Hi, could someone let me know how to measure 1db compression point of a differential VGA using spectre RF. Thanks
I am simulating a Class E RF Power Amplifier in Cadence Virtuoso Spectre. I am just wondering that if it is normal to measure 1dB power compression point of a non linear (switching) power amp like Class E? Why? If yes, then I am not sure if I set up the PSS analysis right. Could you please check it right below? (433MHz is the operating frequency
Hello, I am designing an 30-50GHz CMOS LNA. I have simulate all the necesary parameters except the 1dB compression point and the IIP3. I am using Cadance Virtuoso. Can somebody explain to me how to simulate these two points. I have found some manuals online but they are all for narrow band LNAs. I would really appreciate if someone could (...)
Hello, sometimes the linear dynamic range of square law power detectors is defined between the TSS power level (tangential signal sensitivity) and the 1dB compression point. The books from Maas explain how the TSS value is measured. The term "1dB compression point" is normally used for amplifiers and is defined for po
Hi, I was wondering how does the compression point changes with increasing or decreasing the a) LO power b) LO frequency c) IF frequency.... does it brings any change or for a given mixer the compression point is always fixed at any cost??
Hello everyone, I have a quick question. I designed a LNA ( common Source Cascode LNA) for ultra low power application and everything is at the boundary for 220uW power dissipation. S11=-10dB,S22=-11dB, S21=9.9dB, S12<-40dB, NF<2.5dB, Kf> 20 But my 1 dB compression point and IIP3 point do not make any sense. I am getting IIP3( (...)
You should use PSS analysis in SpectreRF with psin source while Amp(dBm) is changed in convenient limits. In this case you do SPSS ( Swept periodic Steady State ) analysis. When you finished the simulation, SpectreRF automatically will introduce a choise for IPn and compression points ( either output and output ) . For LNa's , "Input IPn (...)
As I see in books and tech notes, SFDR is not often used and seems mainly for ADC and DAC. Why do people use SFDR instead of P-1db point there? Thanks linear dynamic range, which use 1-db gain compression point for the upper side, is used for PA; SFDR is used for LNA and Mixer et al.
When I simulate a resistive FET mixer. The IIP3 points seems to be lower than the 1 db compression point, P-1dB is this possible? I do the simulations in @DS. The results also seems to be hardly dependent on the maximumorder. Therefore I have increased the maximumorder to about 20. I know the rule of tumb IIP3 ≈ P-1dB + 10 (...)
In order to get 1-dB compression point, you need to run PSS simulation
i do not think so, in fact the main pressure is to improve the output 1dB compression point to 10dBm in my design. A shunt or series small resistor( such as 10 ohm) at the collector of the transistor would stable the lna, but decrease the linearity. That is why when i substitutes the ideal lumped inductor with real spiral inductor provided by the d
HI, For the Analog Verification of Mixer Block , there are two Specifications called input 1db that is 1db compression point (which shows the linear region of the mixer ) and Ip3 (third order intercept point ) so while verifying these two specifications , an Extrapolation point has to be selected , so can any one (...)
What's wrong with this 1db Gain compression point analysis?Is it normal?It's not a straight line. (freq=4GHz) and it would be correct to calculate TOI=ip3_in(Vout,15,{1,0},{2,-1},50) in this way I mean setting
If you can plot IF Power (out) vs RF Power (in) then that should be enough. Best done as a swept simulation. At lower input power levels the response should be linear so 1dB extra input RF Power gives 1dB extra IF Power. Imagine that line extending on infinitely. Then at higher input power levels the output power level should start to drop below th
"1 dB compression point" nonlinearity figure of merit is generally not used for receiver circuits. Digitally Modulated signals are simulated or measured as "Bit Error Rate" at the output.You can do this simulatation by defining your receiving chain and it's nonlinearity in a System Simulator or MatLab. In the other hand, ZIF will give you baseband
Dear all, I have a question about the output 3rd-order intercept point simulation frequency setting in up-conversion mixer. I hope anyone could correct me if I am wrong. For example, my upmixer is with input IF, input LO and output RF. For 1dB compression point simulation, I will give input IF=10MHz, input (...)
Hello everyone, i have studied that for a linear system output power should follow the input power. But due to the large signals levels outputs get saturated and the point where the gain drops by 1dB is said to be 1dB compression point. I have plotted the output power vs input power but i am not able to interpret the graphs (...)
I designed an lna,the input-referred 1dB compression point is shown below 76307 With the increase of input power, the LNA gain increased. I think the input-referred 1dB compression point is very strange I feel normal as follows, 76308
Gain expansion happen mostly in Class-AB power amplifiers, mainly due to non-linearities in the device parasitics, especially capacitances. These non-linearities provide a cancellation of the compression point at a specific power level. A device that have one-tone gain expansion, will have also multiple nulls in the high order two-tone inter-mods p
Hello, I would like to know the main-substantial differences between in-band and out-of-band 1dB compression point.(Apart from the obvious difference of the working frequency, I would like to know the effects of it-what saturates first and so on) If there is any known material you can provide please let me know. Thanks.
Hi, I used to work with GaAs circuit (pHemt) and I use the "rule" that IP3 is 8 to 12 dB higher than 1 dB compression point. I am not expert with non linearity effect so I have many question : 1) This "~10 dB" rule is valid for all GaAs circuit ? Amplifier but also Mixer, Phase shifter, switchs ? Is cold pHemt are used this rule still good ?
hi i have designed transimpedance amplifier. but i have doubt in simulating 1 dB compression because in TIA input is current and output is voltage so is it correct to simulate 1dB-CP by using PSS analysis.
The site has a comparison You go to the download lite link and then the compare full to lite link. Generally, it has a smaller number of blocks and does not do some features such as compression point.
Hi, I know the problem with my filter is high impedance. I had asked the Maxim tech help on how about lowering the impedance requirements. (Actually the output impedance of the mixer is around 100-400 ohms but an impedance of 4K is recomended.) I got the following answer. "As the filter impedance is lowered, the mixer ou
To maximize linearity, use a mixer with a high IMD intercept point and a high 1 dB compression point. Then make sure that your signal is much lower than these levels. The optimum point is 2/3 of the way up (in dB power) from the noise floor to the IP. This also applies to all amplifiers, RF and IF in the signal path. You (...)
Have a look at my Linearity tutorial at under systems & devices - I have done a IM3/IM5 & 1dB compression point ADS example. :o
hi Guys: i have been built a four-stage amplifier operating in 2.3GHz to 2.4GHz,which peak output power at the 1dB gain compression point is approximately 500W....Its final stage consists of four balanced 120W BJT. Behaviroal modeling of the high power amplifer is my next u konwn,it is very useful to simulate the system level perfo
Hi. Please explain more about your design. such as the range of input power and 1 dB compression point of your desing. can u use MMIC such as MAR and Era? bests.
I'm about to test a single active mixer of a direct conversion system (zero IF), Is there any good method to do the impedance match on "RF, LO & IF" port, in the precondition that Gain, Voltage 1dB compression point and NF would not be changed obviously, or these these specification could be attained by some calculations from testing data. About
there is a aritcal said , GSM receiver designers specify the receive strips' compression points based on in-band blocking signal level specifications, and uses the out-of-band blocking signal levels to define the filter rejection specifications to avoid signal path compression. Q1 : Why to specify the reciever strips' (...)
Hi, I want to know that for load pull measurement (on wafer devices), do we get the power contour at constant (or 1dB compression point) delivered input power or constant absorbed input power. i always find that paper only use Pin without specification. thanks in advance.
Dear all, Could anyone tell me that where could find out the GPS specification? I want to know how is the phase noise and power is needed to obtain in the VCO? How is the conversion gain of the receiver (from RF to IF), Noise Figure, IIP3 and input 1-db compression point? thanks wccheng
Well all EDA software does is to use models to approximate an answer. And when your are in or around the P-1db compression point, there aren't any modles that can account for all of the the non-linearities. Also for PA's I have found that I got better results when I used the impedance of the device rather than a model. ie. Port1 = 50Ohms
Hi! Does anybody ever seen analytical equation of input 1dB compression point in any reference paper or book?? Many nonlinear Volterra series anaysis is focused on IM3 equation but seldom focused on IP1dB point. Mostly because that IP1dB is in hard nonlinear region, and someone reported that the IP1dB point equation derived (...)
Hai Guys: 1. What shall the output termination resistance range be applied to the output port?. I find that higher settings of resistance value highly improves the Conversion Gain. Output port= IF Port ? In any case, the 3 Loads should be = Zo (i.e. 50 Ohm), Into coax or Waveguide domains, this give a freedom for the us
You must first know the ability of you amps. For example if you have a 10Watt (13dB Gain) PA that means you can get 40 dBm (over some freq range) ! If your input/receive signal 0dBm and you have 2 - 15dB gain driver amps you should be able to get 40dBm out of your PA? (right?) But if your drive amps have -1dB compression point of 25dBm. The s