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Type: Posts; User: vfone

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    Closed: Re: Cellular Power Densities

    I think that "maximum reliability with minimum infrastructure" is the target of any wireless system, not only of the cellular systems.
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    Closed: Re: Cellular Power Densities

    The 5G phase 2 specs (mmWave) are still under development and will be completed in June 2020:

    https://www.3gpp.org/release-16
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    Closed: Re: Trouble with my analyzer ?

    I don't have this instrument but looks like you are in the mode, RF Control: GENERATE.
    From pictures found on the net seems that you will get the Volts indications in the MONITOR mode:
    ...
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    Closed: Re: bfq162 pnp comlementary?

    For HF frequencies up to about 20MHz you can use the PNP BD136 and its NPN pair BD135:
    http://www.svntc.com/TPDF/581.pdf
    http://www.svntc.com/TPDF/576.pdf
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    Closed: Re: Problem about amplifier biasing circuit

    Sometime Ld is replaced by a resistor at the cost of losing efficiency of the circuit.
    Also there are situations (for narrow band circuits) when Ld is not a choke, but is an inductor which together...
  6. Closed: Re: design and simulation of cross-coupled VCO using keysight ADS

    I just found that your DC supply (V_DC) is placed in reverse position.
    If use NPN BJTs, the negative (-) shall be connected to the ground, and positive (+) to the transistor collectors.
  7. Closed: Re: design and simulation of cross-coupled VCO using keysight ADS

    You connected the base of each BJT transistor directly to the other BJT collector, which is wrong.
    The DC bias of the cross-coupled VCO should look as in the schematic below:
    ...
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    Closed: Re: CST: strip line between

    To get the best compromise (impedance matching and radiated power), g should be about 1.5 x Wf.
  9. Closed: Re: Any replacement for 30days, 95% humidity test?

    You can change some parameters as, temperature or humidity, but only if this is not an endurance test.
    "Endurance tests are used mainly to measure the response of a tested element under potential...
  10. [SOLVED]Closed: Re: what's the rf cavity filter tuning principle

    https://d1jiktx90t87hr.cloudfront.net/185/wp-content/uploads/2016/06/Telewave-Cavity-Tuning-July_2017.pdf...
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    Closed: Re: Antenna efficiency from S11

    This is very true.
    Meantime, thousands of antenna papers or antenna books, most of the time when shows performances of the antennas, they provide ONLY S11 (or VSWR) plots...in English there is an...
  12. Closed: Re: Effect of number of fingers and width of a transistor on Efficiency and power gai

    This theory is for GaN but the provided information can be applied to other processes:
    https://publikationen.bibliothek.kit.edu/1000021579/1761764
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    Closed: Re: About Stripline design questions

    In the fundamental mode the stripline conductor is equipotential (every point in it is at the same potential).
    If the top and bottom ground planes are not at the same potential, a parallel-plate...
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    Closed: Re: Broken RF ground plane

    0R resistors is the answer..choosing their optimum size allow routing an RF signal between terminal pads without problems.
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    Closed: Re: Change circuit topology in Smith V4.1

    fritz@dellsperger.net
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    Closed: Re: order of magnitude bias for the diode mixer

    Mixer diodes usually are not DC biased. The diodes are opened by the LO signal. The diodes should behave like ideal switches.
    Meanwhile, the RF detector diodes should be DC biased, to increase...
  17. Closed: Re: Where can I get my transmitter/microwave link tested

    I can bet that transmitting 150W without a license in FM broadcast band is illegal in ALL countries in the world.
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    Closed: Re: PA loadpull impedance location

    Usually the output impedance of a PA is low (or very low) depending by the output power and on how close the last stage is near compression. So the impedance point is placed on the left side of the...
  19. Closed: Re: Is it really "heating" used for beam scanning in Echodyne's radar?

    "...Echodyne, a Seattle-area startup backed by investors that include Bill Gates and Paul Allen, announced that it was working on a new type of radar about the size of a cellphone with performance...
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    Closed: Re: Dual band variable gain amplifier

    To answer to your questions you have to know what receiver type is used by the system. Super-heterodyne (unlikely), direct conversion, low-IF, etc.
    If the VGA is placed after the mixer, there is no...
  21. Closed: Re: How to increase printed meandered dipole antenna bandwidth

    There is not much to do to increase the BW of this antenna type (printed meandered dipole). Its BW is about 7% of central frequency (for 2:1 VSWR). Depending of the dielectric material and its...
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    Closed: Re: Long distance ultrasonic range finder

    Your schematic should work fine at 18ft. I've seen even simpler schematics that works at that distance.
    If the transducer and the RX active filter are on 40kHz, the TX driver filter (C16, L2)...
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    Closed: Re: Using spiral inductor after SRF

    https://www.silabs.com/documents/public/application-notes/an930-efr32-matching-guide.pdf
    https://www.um.edu.mt/__data/assets/pdf_file/0010/113500/Matching_Networks.pdf
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    Closed: Re: how they simulate this 3 stages amplifier?

    You may name C22 a DC block capacitor.
    There are a lot of papers and books available on the net for PA impedance matching. Just search for them....
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    Closed: Re: how they simulate this 3 stages amplifier?

    Q6 stage is a wideband amplifier and doesn't have a specific input/output matching network.
    Q4 use L8 and C27 as output matching network, Q3 use L7 and C22 as output matching network, and Q2 (the...
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