Search Engine

Power Amplifier For Gsm

Add Question

45 Threads found on Power Amplifier For Gsm
great job ,if anyone can tell me how to match the gsm power amplifier By "Load Pull" method. Never use conjugate matching for power amplifiers with high powers. If you have a simulator and nonlinear model of the output stages' transistors, you can "predict" the optimum (...)
The supply current of the power amplifier is converted into a voltage over a sense resistor. A common operational amplifier can read this voltage used to control the gain of the PA.
low cost gsm also available on do not spaming !!! MAX4473 Low-Cost, Low-Voltage, PA power Control amplifier for gsm Applications in 8-Pin QFN
It is known that biasing circuit is critical for power amplifier performance.Can somebody talk about the trade-off between them?Such as from linearity,efficiency,temperature stablity,biasing stability points of view? Thanks!
Hi I want to design an RF power amplifier. but I know almost no thing!! pls help me. Which blocks are there in power amplifier? power transistor? power supply? combiner? ... Is there any simple block diagram?
I want to build a hight power amplifier (30 or 40W ) for gsm 900. any design or example :?:
I need help for gsm power amplifier design ( both 900 and 1800 MHz separately) with 20 dBm input and 40 dBm output. I need a fast and practical solution, so a gsm power amplifier chip with application circuit will be very useful for me. I may also want to (...)
Max allowed TX levels (Watt) for some common systems: gsm 900: 2 gsm 1800: 1 UMTS 2100: 0.126 LTE: 0.250 power level is dynamically reduced depending on how good connection is with base radio. Some systems are transmitting in short time slots. Due to this have for example gsm 900 (...)
Since a lot of time polar transmitter (power amplifier) publications are available and proposed for cellular handsets, e.g. from Tropian ( ) for non-constant envelope standards. But this architecture has not established. As far as I see, only few EDGE PAs are based on this, but no CDMA. What are the reasons? And what are (...)
The power amplifier will present a load impedance to the oscillator. This load impedance will change as the power amplifier is brought from the standby to the full operational mode. By analogy of the old days of magnetrons whose frequency was partially determined by the load impedance it was driving, this is called (...)
Hello, Please help me to understand this term, Peak to average power ratio , with respect to a transmitter (power amplifier design) . In a system employing pi/4DQPSK modulation , 4 slot TDMA system at data rate of 36Kbps what would be the peak to average ratio. To be specific it is required to know the peak to average ratio in a TETRA (...)
Hi, for gsm RF system. I'm trying to investigate TXVCO loading unmatched to 50 Ohm problem. Let me say, if here exists TXVCO output cascaded into RF power amplifier, what if NOT 50 ohm load trace really happens. If we temperarilly disregard varying input impedance at different output power level of (...)
i have study the document of the LTC1758-1/-2, in fact this is a simple over drive kind circuit of the PA, the loop bandwidth is a measurement of response time! for example when the power amplifier output power is over the limited rate, then this chip shall shut down the PA, then the PA output power is zero, (...)
I need help in choosing a simulation package(software) to simulate a gsm phone repeater operating on 1900 MHz or 850 MHz which are the 2 main frequency band used in Canada. Does anybody knows how to do this or anybody have done this simulation and I need help to first simulate this and then of course impelment the unit. However, at this stage I
I am working on an amplifier module as specified below: - Work on 800 to 1900 MHz band. - 2 Watts output - input as low as 0 dBm Can someone suggest a good RF power amplifier module (IC) please.
the switching classes of the power amplifier , the active element "mos, bjt , HEMT" used as a switch to on and of like classe E , D power amplfiers they are a nonlinear classes , and need linearization techniquies khouly
gsm-850 specification for noise power is -79 dBm, in the frequency band 869 MHz to 894 MHz using a RBW of 100kHz. Check that you use the right RBW for the measurement. for this test you need a notch or a band-reject filter to reduce the TX carrier. In this way you can increase the dynamic range of the (...)
hi... why use multistage...? maximum gain for single stage power amp?
Hi! If anyone was interested to view microcontroller projects such as RFID card lock, or gsm controller, or if you wanted to build high-power amplifier, 250W or 500W sine power, you could download and build them: I hope you'll like it :) johnny_hush
I am basically working on dual band Cell phone jammer. I will jam two gsm bands i.e; gsm 900 & gsm 1800. It will cosists of two parts: 1)IF section 2)RF section In the IF section following components will made; a)Triangular wave generator (Sweep generator) b)Noise generator c)Mixer d)Clamper RF section contains following parts: (...)
I would like to generate high power (several kW) rectangular wave at 200 MHz. 1) Can anyone recommend properly broadband (0.2 - 2 GHz) power transistors for this purpose? 2) What would be the best way to load a 200 MHz resonant LC circuit using such a square wave?
Thank you............. I have attached mobile phone speaker to gsm modem ... so any way its volume is less... so what can i do to get more volume ...... try wearing a mini power amplifier, the input from these speakers while the PA output decoder 8870 connected to the input .... so I can better understand
Thanks a lot tony_lth but Couldn't find any help Actually i needed a schematic of a 1.8Ghz power amplifier as i am doing a project in ADS on gsm Band Jammer Circuit. So if anyone could help??
what is the purpose of combiner in case of power combining. Suppose there are two amplifiers both have output power of 10 watts.IF there is 3db insertion loss , it means there is half power loss for each amplifier. At the output of the combiner there will be 10watts power . (...)
The given information is very few and that's why it's hard to say something for a solution. But in ADS Load Pull Design Guide can be used to find Optimum Load Impedance for your power amplifier. Nevertheless, don't trust too much nonlinear model of the transistor instead ask to manufacturer (...)
Constant envelope signals can go through class C amplifiers. Nonconstant types have to go through class B with a lot of backoff to keep the out of channel power down. There is a big difference in DC power input between these two methods for the same RF output power.
Basically voltage and temperature effects on circuits are non-ideal or unwanted situation you'd like to see. Thus people use thermistor, voltage sensing feedback control to compensate them. for TX-RX transiver system, voltage variation is important to supply pushing effect which may degrade your performance, and for power (...)
Hi, attached please find a presentation file from Agilent (you can also find it at the agilent web site). Using an isolator before the power combiner is important because some power from one of the signal generators may be coupled to the other signal generator and may cause inaccuracies. Of course, you have to calibrate your measurement (...)
Because GMSK is a constant amplitude signal, the power of the modulated signal is constant. Because of that, you can use a compressed, non-linear amplifier for GMSK.
there are many circuits that are floating on the web. If you are new to RF circuity then I strongly suggest you stay off building such things as it is not easy to work with and even the slightest change in the board that you use will tune-out the device etc. I am no
Dear all, I have two quistions... 1) Why CDMA systems (UMTS,IS-95,CDMA2000) use QPSK modulation technique while TDMA system (e.g gsm) use GMSK modulation? 2) Why modulation used in Downlink is different than that is used in Uplink? (as WCDMA DL use QPSK while WCDMA UL use BPSK). Thanks in advance. 1) GMSK is use
i use the AD8313 to do the power detector ,the result in gsm power amplifier, at dirst i use the gsm signal from the E4438C and then use the WCDMA, the result is the solpe is the same and the offset is different, i think the simulation is only a guide; at last i use the AD8362 to solve this problem
Hi all, I am having a board with an interface that is providing 5V@1.5 mA to a Card Reader. I need to replace Card Reader with gsm module which requires 5V@2 mA. Can I generate the current required by gsm module from the existing circuitry by using current amplifiers. If yes, then please tell me which current (...)
1)for PA forward isolation, it means when the PA is shutdown (no power supply), the power coupled from input to output. It's used in gsm handset power amplifier module filed.
Hi guys , i want to design a bandstop filter in gsm frequency ( 870 Mhz - 960 Mhz ) with hfss , I am an amateur. This filter is for transmittering antenna and my prof wants the filter's capacity upto 200 watt , I have searched about high power filters but I can't find anything useful... The other problem is that I want to design a (...)
... when I plot the output FFT how do I separate the signal components from supply EMI components? How can I get PSRR value? Run 2 (or 3) separate ac analyses: One with signal only (no EMI on pwr supply), another one (or 2) with your selected EMI configurations (the gsm one, or your battery charge variations) on the power
Dear Expert, two gsm 1800 band signals(2 different operator in IBS site share trial project) with different power level ( 17 dB and 30 dB) in the same feeder cable. this cable goes to........> 15 DB coupler then 10 DB coupler. the remaining ports of 2 coupler were terminated by dummy load. Now the cable goes to the i/p of a line a
Hi. I am design a Class E RF power amplifier operating at 433MHz. The Class E PA is non-linear PA due to the nature of its operation. So do you think if noise figure measurement is necessary for the non-linear PA? I haven't seen this in papers I read. Thanks.
The simplest way is to use a 50-Ohm power splitter. If you can afford to lose some RF power, you can make such power splitter with resistors, a triangle of 25-Ohm resistors can offer a good match but ~ 6 dB loss. If you use the two antennas with a low-noise receiver, use the power splitter, or, add (...)
In gsm, the 217Hz is a sensitive issue and happened due to the 4.6 msec TDMA operation of the RF power amplifier. The most important thing to avoid this problem is the layout design of the audio circuits of the mobile, mainly following the old rules of the audio amplifiers PCB design (a lot of designers don't follow, or do (...)
I suppose the only place where you may need an inrush current limit is between the battery and the reservoir capacitor of 1000uF. Depending on the internal resistance of the capacitor there may be overcurrents at startup. In normal use I would think the idea of a NTC resistor in the power supply line is neither good not necessary. If you select a c
With Supply Voltage Control, the collector or drain voltages of the last one or two amplifier stages are controlled. This limits the voltage swing of the RF power transistors. Advantages: - Output power is predictable after a simple calibration - If is TDMA (gsm) the burst template (power versus time) can (...)
u need a good power amplifer to kill the phones :D khouly
Could i power the mobile phone without battery , only using 5Vdc supply ? if it's possible how i connect to the mobile power pins, i know that there are 3 pins 2 of them 0 and 3.3V from battery but the 3rd ???
and gsm modem needs about 4.2v MJD122 , check out the data sheet The Vce saturation voltage drop may cause problems if the power supply voltage is close to the needed 4.2v and there is not enough headroom