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Hi all,
What type of matching should I use for input matching network at transistor gate? The signal that drive the gate is a modulated square wave, which mean looking from spectrum is a few harmonic around 1 GHz frequency(between 0.925GHz-1.075GHz). If I match using stub technique, the...
Hi all,
I made a circuit with LC tank resonator as shown below without any microstrips element and the result of S-parameter shows a resonant amplitude at 1GHz ( f_res = 1/2*pi*sqrt(LC) ). When I integrate microstrip lines into the schematic, the S-parameter result now shows an attenuation at...
Hi all,
I have this problem every time I increase the value of RF chokes (L4 and L5) above 5nH. The simulation gave an error message:
" Internal timestep 5.90440e-24 too small at time 4.00940e-10. "
How could I solve this problem? I'm designing current mode class-D RF amp with HEMT as used...
Hi all,
I need to design Current Mode Class-D (CMCD) PA with modulated PWM signal as an input and encounter these problems. I describe step by step the design I done and the problems I encounter in the pdf file below.
Hope any of you can show me which part I did wrong.
Thanks a lot.
Hi all,
I came across this RF class-D power amplifier design and want to know, what type of input matching has been used here? I cant really understand the input matching schematic below(shown in the red region). Is it only for matching purpose or is there any other purpose? Could someone...
I use rat-race hybrid/coupler to have a 180 degrees phase shift. I give my PPM signal at the input of the coupler, and I get 2 outputs of the same signal that differs by 180 degrees phase. But this doesn't allow only 1 transistor works at a time. The signals can be seen below.
I'm actually designing a class-D power amplifier (shown in circuit below) using delta sigma modulation as the modulation method. The output signal(PPM) which should be fed to both transistors, is similar to PWM, as shown by the image below.
So i have this PPM. The question is why most...
So does it mean the transistors will be driven by both signals, which are product of modulation with carrier frequency and its phase-shifted signal(inverted signal) as shown below? Is it right?
Hi all,
In Class-D amplifier, the transistors are in Push-Pull configuration. To drive the transistors using the PWM signal, the signal given at either transistor is inverted of the other signal.
The question is:
From most of the references I read, why they normally used 180 degree phase...
Hi all,
I am designing this CMCD-PA using Agilent ADS. I would like to know, why did the voltage at output load (R4) form a half sinusoidal shape?
Shouldn't it be a full sinusoidal waveform, similar to the current at R4??
You can refer to my schematic and the output in the attachment below.
TQ
Hi all,
I need to develop a project, which detect a circuit is opened(current doesnt flow) or closed(current flow) and transmit the information via bluetooth.
So, my question, if im using bluetooth module, do i need a microController to read the input of the circuit, either the circuit is...
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