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  1. lewisFeng

    Easier way to realize a 2FSK LO in Xband

    The AFC is more like a frequency fine tune method with switch time of several us. My LO has 240MHz adjust range with step of 1MHz. So if I can use MOS SPDT between two Fractional-N PLL with the speed of 20ns with isolation of 60dB, the circuit is greatly simplified. But during rise-fall time the...
  2. lewisFeng

    Easier way to realize a 2FSK LO in Xband

    Dears, My current solution is Generate it at DDS and then modulate on L-band, then up-convert to X-band. This solution need a lot of components include a dds, two PLL, two Mixer and lots of amplifiers and filters and attenuators. Because the 2FSK modulation is two simple, I'm wonder if there is...
  3. lewisFeng

    DSRC

    Hi, do anyone has the experience of DSRC on board unit design? I'm looking for the state of art product. I only see Savari's website. Do there any system exactly base on the latest IEEE 802.11p amendment 6?
  4. lewisFeng

    High isolation of side by side subarrays

    Oh, Ubiquiti also ready realized the same thing in parabolic antenna, but they call it 2X2 MIMO without diplexer. It is base on HDD(hybird domain diplexer), including both FDD and TDD. And it can obtain a unbalanced air port capacity. http://www.ubnt.com/airfiber
  5. lewisFeng

    Modification of IPhone5

    Yes, you are right. It is difficult to realize an EVDO USB Modem without SIM card. That is to say if I can't setup a route to the SIM card inside through lightning connector, the only way is to capture SIM infomation in air. So it is preposterous.
  6. lewisFeng

    Modification of IPhone5

    I always appreciate your system advices and the Higgler's design tips, you are the tutors here. But you know the client's demand is everything, they always believe 'Anything one man can imagine, other men can make real'. The fact is Samsung is expelled from USA's smartphone market due to the bit...
  7. lewisFeng

    Modification of IPhone5

    Dear friends Now I'm doing a project to add the third RF path to Iphone5, for it can't accomplish the task of SVDO (simultaneous voice and EVDO). This is a big problem for subscribers using Verizon and Sprint's network. You may know the orientation of antennas on Iphone, to describe it clearly...
  8. lewisFeng

    High isolation of side by side subarrays

    Hi, Higgler. What's no common radome meaning? Would you reveal littile more.
  9. lewisFeng

    Gap waveguide from millimeter wave up to THz

    Do anyone noticed the new technology of gap waveguide? I don't expect metamaterial go that far. It seems this type of waveguide is suitable for integration of MMICs and antenna above 30Ghz. But I don't see any large antenna array realized in this technology. It mostly appeared in Gothenburg's...
  10. lewisFeng

    High isolation of side by side subarrays

    I was interested in the echo cancellation topics, because either the double reflection of the feed line or the multipath reflection can be viewed as echo sources. I want to explain the system with more detail. For Eband(71~86G), the pathloss is 92.4+20*log80Ghz+20*log2km=136.4dB, and each...
  11. lewisFeng

    High isolation of side by side subarrays

    Dears In microwave and millimeter communication, diplexer is used for division of TX and RX. But one of our supplier provide a solution by two high isolated side by side subarrays. By the 75dB~90dB isolation(with same polarization), the diplexer can be obviated. I guess this merits is obtain by...
  12. lewisFeng

    Artificial magnetic conductor in UHF

    Dear, Is there anyone familiar with Artificial magnetic conductor(AMC)? I'm design ultra-low profile antenna in UHP, I need this material to use as ground plane. In this paper the AMC is manufacture by a dielectric substrate MCT-25 with relative dielectric permittivity 25 in 2.54mm thickness. Do...
  13. lewisFeng

    Acoustic interaction measurement

    Yes, I already have the mathematic inductive field interaction model. But the buzzer is outsourcing item, the electrical and mechanical parameter is very hard to calculate or simulate.I want to figure it out by relative test method.I thind it's no problem to view the microphone as a nearfield...
  14. lewisFeng

    Acoustic interaction measurement

    I need measuring two buzzer working on 40Hz to verify the interaction to the circuit and SPL. Below is my test schematic figure, I planed to use the free version of TrueRTA to measure the SPL, do any suggestion? should I prepare rheostat or variometer or varicapacitance to measure the impedance...
  15. lewisFeng

    60Hz to 40Hz transducer

    I haven't see any commerial VDF change 40hz to 60hz, maybe it should be customized designed. The total amount of buzzers is about 100 pcs. So the average power consuming maybe more than 300w, and the average current maybe more than 2.5A, the instantaneous current maybe higher. Because the system...
  16. lewisFeng

    60Hz to 40Hz transducer

    Actually, I'm a antenna designer.The project is a buzzer array work on 40Hz. The passive electromagnetic buzzer should be drived with the external signal with 40hz 110V AC, and the preferred waveform is not sine wave but half square wave. The question is if the power is 60hz 110v AC, how do I...
  17. lewisFeng

    60Hz to 40Hz transducer

    Dear professionals I need to build a power tranducer to drive a eletromagnetic buzzer.The residential electricity in USA is 110V 60Hz, I need the output to be 110V 40hz in square wave with with limited output current. How can I get the transducer, please help, thank you in advance.
  18. lewisFeng

    Acoustic array of 40Hz

    Finally, I move from Antenna & Propagation to here. I have a project using more than 100 acoustic electromagnetic buzzer to get the strongest pressure at a 3m away target. Actually the buzzer is acoustic small at 40Hz, about 25mmX25mmX25mm in size. According to the requirement the array can not...
  19. lewisFeng

    Acoustic array of 40Hz

    Do anyone here have the knowledge about acoustic array made up by many microphones. The array will be used for probing of the atmospheric boundary layer. I want to know the best method to simulate it and calculate the mutual coupling effect between elements. Thank you in advance!
  20. lewisFeng

    CTS antenna and Thinkom

    Thank you for your advice.I'll follow the patent to sourcing more supplier. I'll pay more attention during the negotiation. attached is the IEEE file...

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