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Type: Posts; User: jayleung

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  1. Closed: RF/Baseband SSB (single-side band) modulation signal questions

    Hi All,

    I have a question about the SSB (single-side band) modulation signal, and its circuit implementation in Radio.

    For example, the baseband DAC has two I/Q differential signal outputs,...
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    Closed: Quad band antenna for GSM bands

    Most of the antenna companies are now working on quad-band, or even penta-band antenna.

    Basically the PIFA/monopole type antennas with some matching circuits would work. Of course, the VSWR/RL...
  3. Closed: Working in 4W (36dBm Power out in RF) at 200 to 250MHz

    I believe 4W is not a big problem. If I remember correctly, most cell phones have up to 30~33 dBm conducted power.

    But of course, if your antenna is directional, don't point the main beam to...
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    Closed: Re: What's the balanced amplifier noise figure

    I am wondering how can I calculate that? Are there any formula to do so?

    The other issue is that why the matching resistors do not contibute addtional noise to the output? If these resistors is...
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    Closed: What's the balanced amplifier noise figure

    Hi, I have a question about calculating the noise figure of a balanced amplifier circuit, as shown in the attachment.

    In this case, two LNA is followed by a 90-deg hybrid coupler splitter, and one...
  6. Closed: minimum component spacing in the automatic pick-and-place

    Hi, everyone. I have a question about the minimum component spacing in the automatic pick-and-place assemble process.

    Let's say that I design a complete circuit with all kinds of components, with...
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    Closed: Wilkinson divider power distribution

    Just a simple simulations for the above situation, it gets:

    S11=-6dB (25%)
    S21=-3dB (50%)

    It means that if the resistor is working, half of the input power from port 1 goes to port 2, 25% of...
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    Closed: simple quesiton about spectrum analyzer

    I have a simple question about the spectrum analzyer.

    Is it used to measure the power spectrum density(PSD), so the measure output unit should be dBm/Hz or W/Hz?

    But it seems the real world...
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    Closed: PCB plating thickness

    Hi, I have a general question about PCB manufacturer.

    The fab house told me that when I use 1/2OZ copper foil (.7mil) on external layer, after plating additional copper for PTH, it goes to about...
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    Closed: RF LNA chip test procedures?

    Hi, I have a question about RF LNA chip test procedures.

    The LNA have been soldered on the PCB, with RF in, out connected to SMA connectors, and DC pin to regular connector. It is self-biased MMIC...
  11. Closed: intermodulation order

    Hi, I have a question about the third order intermodulation product (IP3).

    I understand that for two single tone signals at f1 and f2, the IP3 appears at 2*f1-f2, and 2*f2-f1. But if those two...
  12. Closed: a question about PCB layout for 3-stage single chip PA

    Thanks Dipnirvana.

    Another questions about the decoupling capacitor. Can I just connect the 0402 100pF capacitors adjacent to each Vdd and Vgg, and then tied them together, and connect the...
  13. Closed: a question for pcb

    Hi, everyone. I have a question about the PCB layout for a 3-stage single chip PA.

    As shown in the attached picture, the PA is in QFN package, with 3 stage amplifier inside. Each stage has its own...
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    Closed: pc spi

    Hi, everyone. I am pretty new to embedded systems design, and have a simple question about letting PC to generate SPI signal. Are there any evaluation board that can enable personel computer to...
  15. Closed: gold plating pdf

    Hi, I have a question about the PCB finish plating processing:

    For the electroless nickel immersion gold plating (ENIG), is the processing like:

    plating->etching->solder mask

    For the...
  16. Closed: bypass capacitor at 35 mhz

    good answer!

    Just another simple question, I found that even the same size, same capacitance, same series capacitor, the voltage rating does not affect the unit price?

    Does it mean that I...
  17. Closed: ceramic bypass capacitor

    I have a simply question. For DC power supply, can the general 0402/0603 ceramic capacitor be used for bypass capacitor?

    Thanks.
  18. Closed: dc cable ends

    Hi, I have a question about buying the DC power cable and connector for the agilent DC power supply E3631A.

    1. This power supply have some plug-ins for the DC power output. I am wondering what...
  19. Closed: embedded stripline

    Hi, everyone. I am wondering when designing the embedded stripline circuit, how can I measure it? In detail, how can I insert the SMA connector to measure the stripline circuit? Thanks.
  20. Closed: how to determine printed antenna power handling capability

    Hi, everyone. For the textbook, it always says that the printed microstrip antenna power handling capability is relative low. I am wondering how can I determine the power handling capability of the...
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    Closed: phase shifter for 60 GHz range

    I am wondering what types of phase shifter can be used in 60GHz range? Any information or materials will be welcomed. Thanks.
  22. Closed: Choosing the way to solder the SMT component during PCB plating finish

    Hi, everyone. I am a newbee for the PCB design. I have a simple question about the PCB plating finish.

    Actually, the PCB houses offer some option about the final plating finish, with:

    leaded...
  23. Closed: quarter-wavelength transformer design with IE3D in mm-wave

    Thanks, Jian. I reviewed the structure and find that once I reduced the distance between the top and the middle metal strip layers, the transformer worked better.

    So I think even though I...
  24. Closed: quarter-wavelength transformer design with IE3D in mm-wave

    Thanks, Jian. So do you mean that if I use multi-section impedance transformer or taper transformer, the design will be improved?

    And just one more question, why the magnitudes of the S-parameter...
  25. Closed: quarter-wavelength transformer design with IE3D in mm-wave

    Hi, Balaguru thavamani. I am not quite sure which version of IE3D you are using. My IE3D version is 11, and the chapter 9 is "Lumped element extraction and signal integrity". It does include the...
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