Dielectric Resonator Oscillators (DRO) are used widely in today's electronic warfare, missile, radar and communication systems. They find use both in military and commercial applications. The DROs are characterized by low phase noise, compact size, frequency stability with temperature, ease of integration with other hybrid MIC circuitries, simple construction and the ability to withstand harsh environments.
These characteristics make DROs a natural choice both for fundamental oscillators and as the sources for oscillators that are phase-locked to reference frequencies, such as crystal oscillators.
This paper summarizes design techniques for DROs and the voltage- tuning DRO (VT-DRO), and presents measured data for them including phase noise, frequency stability and pulsing characteristics.
Design Techniques
The design technique we will discuss is for a dielectric resonator (DR) to be used as a series feedback element. Practically, a GaAs FET or a Si-bipolar transistor is chosen as the active device for the oscillator portion of the DRO circuit. The Si-bipolar transistor is generally selected for lower phase noise characteristics, while the GaAs FET is required for higher frequencies.
For example, a DRO with a DR as a series feedback element can be designed using following design procedure:
1. Select an active device that is capable of oscillation at the design frequency, and use the small signal S-parameter of the device for the design.
2. Add a feedback circuit to ensure that the stability factor of the active device with the feedback circuit is less than unity with enough margin.
3. Create an active one-port analysis that consists of the active device, the feedback circuit, the matching network and the load as shown as figure1. Optimize Za (?) with the parameters in the feedback circuit and in the matching network to ensure that Ra (?0) is less than or equal to -25 ohms and Xa (?) has the possible maximum variation near resonance in order to insure high circuit Q.
Wednesday, December 17, 2008
Monday, December 1, 2008
Wireless Support
At this moment only the RT25USB-SRC-V2.0.7.0 driver from Ralink is succesfully ported and reported to be working with an ASUS WL-167G USB dongle on 2.6.5-it0. This tutorial gives enough information to easily use the ASUS WL-167G on your OSD, but also gives enough information for everyone who wants to port another driver.
So what do you need:
* kernel 2.6.5-it0 with wireless extensions enabled, this is due to the broken USB Host driver in 2.6.15 (instructions below)
* dongle with RT2570 chipset, see serialmonkey for a list
* the source code of the dongle driver. I've succesfully 'ported' the RT25USB-SRC-V2.0.7.0 driver from Ralink
* and some version of wireless tools to send commands to the dongle, available here
* wireless support has only been tested with the developer OSD (green PCB). If you have the yellow/orange one shipped from thinkgeek then you could be the first to get wireless working on a BETA sample!
The broken USB Host driver is expected to be fixed by the manufacturer around 9/12. Until this time you will have to downgrade your OSD to a 2.6.5 kernel... and probably has the consequence that you can't play any video/audio :P
So what do you need:
* kernel 2.6.5-it0 with wireless extensions enabled, this is due to the broken USB Host driver in 2.6.15 (instructions below)
* dongle with RT2570 chipset, see serialmonkey for a list
* the source code of the dongle driver. I've succesfully 'ported' the RT25USB-SRC-V2.0.7.0 driver from Ralink
* and some version of wireless tools to send commands to the dongle, available here
* wireless support has only been tested with the developer OSD (green PCB). If you have the yellow/orange one shipped from thinkgeek then you could be the first to get wireless working on a BETA sample!
The broken USB Host driver is expected to be fixed by the manufacturer around 9/12. Until this time you will have to downgrade your OSD to a 2.6.5 kernel... and probably has the consequence that you can't play any video/audio :P
Wireless LAN
A wireless LAN or WLAN or wireless local area network is the linking of two or more computers or devices using spread-spectrum or OFDM modulation technology based to enable communication between devices in a limited area. This gives users the mobility to move around within a broad coverage area and still be connected to the network.
For the home user, wireless has become popular due to ease of installation, and location freedom with the gaining popularity of laptops. Public businesses such as coffee shops or malls have begun to offer wireless access to their customers; some are even provided as a free service. Large wireless network projects are being put up in many major cities. Google is even providing a free service to Mountain View, California[1] and has entered a bid to do the same for San Francisco.[2] New York City has also begun a pilot program to cover all five boroughs of the city with wireless Internet access.
For the home user, wireless has become popular due to ease of installation, and location freedom with the gaining popularity of laptops. Public businesses such as coffee shops or malls have begun to offer wireless access to their customers; some are even provided as a free service. Large wireless network projects are being put up in many major cities. Google is even providing a free service to Mountain View, California[1] and has entered a bid to do the same for San Francisco.[2] New York City has also begun a pilot program to cover all five boroughs of the city with wireless Internet access.
Wireless Amplifier
In November 2006, Marin Soljačić and other researchers at the Massachusetts Institute of Technology applied the near field behaviour well known in electromagnetic theory to a wireless power transmission concept based on strongly-coupled resonators.[12][13][14] In a theoretical analysis (see Ref: Annals of Physics), they demonstrate that, by designing electromagnetic resonators that suffer minimal loss due to radiation and absorption and have a near field with mid-range extent (namely a few times the resonator size), mid-range efficient wireless energy-transfer is possible. The reasonment is that, if two such resonant objects are brought in mid-range proximity, their near fields (consisting of so-called 'evanescent waves') couple (evanescent wave coupling) and can allow the energy to tunnel/transfer from one object to the other within times much shorter than all loss times, which were designed to be long, and thus with the maximum possible energy-transfer efficiency. Since the resonant wavelength is much larger than the resonators, the field can circumvent extraneous objects in the vicinity and thus this mid-range energy-transfer scheme does not require line-of-sight. By utilizing in particular the magnetic field to achieve the coupling, this method can be safe, since magnetic fields interact weakly with living organisms.
On June 7, 2007, it was reported that a prototype system had been implemented.[10][11] In an experimental demonstration (see Ref: Science), the MIT researchers successfully demonstrated the ability to power a 60-watt light bulb wirelessly using two copper coils of 60cm diameter that were 2m (7ft) away at roughly 45% efficiency. The coils were designed to resonate together at 10MHz and were oriented along the same axis. One was connected inductively to a power source, and the other one to a bulb. The setup powered the bulb on, even when the direct line of sight was blocked using a wooden panel.
"Resonant inductive coupling" has key implications in solving the two main problems associated with non-resonant inductive coupling and electromagnetic radiation, one of which is caused by the other; distance and efficiency. Electromagnetic induction works on the principle of a primary coil generating a predominantly magnetic field and a secondary coil being within that field so a current is induced within its coils. This causes the relatively short range due to the amount of power required to produce an electromagnetic field. Over greater distances the non-resonant induction method is inefficient and wastes much of the transmitted energy just to increase range. This is where the resonance comes in and helps efficiency dramatically by "tunneling" the magnetic field to a receiver coil that resonates at the same frequency. Unlike the multiple-layer secondary of a non-resonant transformer, such receiving coils are single layer solenoids with closely spaced capacitor plates on each end, which in combination allow the coil to be tuned to the transmitter frequency thereby eliminating the wide energy wasting "wave problem" and allowing the energy used to focus in on a specific frequency increasing the range.
Beginning in the early 1960s resonant inductive wireless energy transfer was used successfully in implantable medical devices [15] including such devices as pacemakers and artificial hearts. While the early systems used a resonant receiver coil later systems [16] implemented resonant transmitter coils as well. These medical devices are designed for high efficiency using low power electronics while efficiently accommodating some misalignment and dynamic twisting of the coils. The separation between the coils in implantable applications is commonly less than 20 cm. Today resonant inductive energy transfer is regularly used for providing electric power in many commercially available medical implantable devices.[17]
Wireless electric energy transfer for experimentally powering electric automobiles and buses is a higher power application (>10kW) of resonant inductive energy transfer. High power levels are required for rapid recharging and high energy transfer efficiency is required both for operational economy and to avoid negative environmental impact of the system. An experimental electrified roadway test track built circa 1990 achieved 80% energy efficiency while recharging the battery of a prototype bus at a specially equipped bus stop [18] [19]. The bus could be outfitted with a retractable receiving coil for greater coil clearance when moving. The gap between the transmit and receive coils was designed to be less than 10 cm when powered. In addition to buses the use of wireless transfer has been investigated for recharging electric automobiles in parking spots and garages as well.
Some of these wireless resonant inductive devices operate at low milliwatt power levels and are battery powered. Others operate at higher kilowatt power levels. Current implantable medical and road electrification device designs achieve more than 75% transfer efficiency at an operating distance between the transmit and receive coils of less than 10 cm.
On June 7, 2007, it was reported that a prototype system had been implemented.[10][11] In an experimental demonstration (see Ref: Science), the MIT researchers successfully demonstrated the ability to power a 60-watt light bulb wirelessly using two copper coils of 60cm diameter that were 2m (7ft) away at roughly 45% efficiency. The coils were designed to resonate together at 10MHz and were oriented along the same axis. One was connected inductively to a power source, and the other one to a bulb. The setup powered the bulb on, even when the direct line of sight was blocked using a wooden panel.
"Resonant inductive coupling" has key implications in solving the two main problems associated with non-resonant inductive coupling and electromagnetic radiation, one of which is caused by the other; distance and efficiency. Electromagnetic induction works on the principle of a primary coil generating a predominantly magnetic field and a secondary coil being within that field so a current is induced within its coils. This causes the relatively short range due to the amount of power required to produce an electromagnetic field. Over greater distances the non-resonant induction method is inefficient and wastes much of the transmitted energy just to increase range. This is where the resonance comes in and helps efficiency dramatically by "tunneling" the magnetic field to a receiver coil that resonates at the same frequency. Unlike the multiple-layer secondary of a non-resonant transformer, such receiving coils are single layer solenoids with closely spaced capacitor plates on each end, which in combination allow the coil to be tuned to the transmitter frequency thereby eliminating the wide energy wasting "wave problem" and allowing the energy used to focus in on a specific frequency increasing the range.
Beginning in the early 1960s resonant inductive wireless energy transfer was used successfully in implantable medical devices [15] including such devices as pacemakers and artificial hearts. While the early systems used a resonant receiver coil later systems [16] implemented resonant transmitter coils as well. These medical devices are designed for high efficiency using low power electronics while efficiently accommodating some misalignment and dynamic twisting of the coils. The separation between the coils in implantable applications is commonly less than 20 cm. Today resonant inductive energy transfer is regularly used for providing electric power in many commercially available medical implantable devices.[17]
Wireless electric energy transfer for experimentally powering electric automobiles and buses is a higher power application (>10kW) of resonant inductive energy transfer. High power levels are required for rapid recharging and high energy transfer efficiency is required both for operational economy and to avoid negative environmental impact of the system. An experimental electrified roadway test track built circa 1990 achieved 80% energy efficiency while recharging the battery of a prototype bus at a specially equipped bus stop [18] [19]. The bus could be outfitted with a retractable receiving coil for greater coil clearance when moving. The gap between the transmit and receive coils was designed to be less than 10 cm when powered. In addition to buses the use of wireless transfer has been investigated for recharging electric automobiles in parking spots and garages as well.
Some of these wireless resonant inductive devices operate at low milliwatt power levels and are battery powered. Others operate at higher kilowatt power levels. Current implantable medical and road electrification device designs achieve more than 75% transfer efficiency at an operating distance between the transmit and receive coils of less than 10 cm.
WLAN WI-FI Solutions
* TrangoLINK Giga® is a split-architecture (ODU/IDU) full duplex RF microwave system link that is both native Ethernet and native-TDM.
* TrangoLINK® Apex is an all-outdoor full duplex RF microwave radio that is native-Ethernet for 100% IP traffic.
* ATLAS 4900™ is an all-outdoor native Ethernet OFDM 4.9 GHz wireless bridge that operates in the licensed Public Safety band.
Unlicensed Point-to-Point Wireless WAN Radios
* TrangoLINK-45™ is an all-outdoor, native Ethernet, multi-band OFDM wireless Ethernet bridge that is capable of operation in 4 different 5 GHz bands (5.2, 5.3, 5.4, 5.8 GHz).
* TrangoLINK-10™ is an all-outdoor, native Ethernet 5.8 GHz wireless bridge.
Unlicensed Point-to-MultiPoint Wireless WAN Radios
For delivering point-to-multipoint (PtMP) broadband access wireless WAN connectivity from a central office to many remote offices, Trango offers these robust solutions.
* Access5830™ System 5.8 GHz broadband wireless access system delivers up to 10 Mbps up to 18 miles.
* Trango M2400S™ 2.4 GHz broadband wireless access system delivers up to 5 Mbps up to 25 miles.
* Trango M900S™ 900 MHz broadband wireless access system delivers up to 3 Mbps up to 20 miles.
* TrangoLINK® Apex is an all-outdoor full duplex RF microwave radio that is native-Ethernet for 100% IP traffic.
* ATLAS 4900™ is an all-outdoor native Ethernet OFDM 4.9 GHz wireless bridge that operates in the licensed Public Safety band.
Unlicensed Point-to-Point Wireless WAN Radios
* TrangoLINK-45™ is an all-outdoor, native Ethernet, multi-band OFDM wireless Ethernet bridge that is capable of operation in 4 different 5 GHz bands (5.2, 5.3, 5.4, 5.8 GHz).
* TrangoLINK-10™ is an all-outdoor, native Ethernet 5.8 GHz wireless bridge.
Unlicensed Point-to-MultiPoint Wireless WAN Radios
For delivering point-to-multipoint (PtMP) broadband access wireless WAN connectivity from a central office to many remote offices, Trango offers these robust solutions.
* Access5830™ System 5.8 GHz broadband wireless access system delivers up to 10 Mbps up to 18 miles.
* Trango M2400S™ 2.4 GHz broadband wireless access system delivers up to 5 Mbps up to 25 miles.
* Trango M900S™ 900 MHz broadband wireless access system delivers up to 3 Mbps up to 20 miles.
Wireless WAN Solutions
Extend your network infrastructure with long range
outdoor wireless Ethernet connections
Trango's long range fixed wireless broadband Ethernet equipment is ideal for all types of wireless wide area network (WWAN) and wireless local area network (WLAN) applications. Trango outdoor wireless networking solutions allow you to quickly, easily, and cost effectively deploy reliable, high-speed, secure wireless IP connections between multiple remote locations at distances up to 45+ miles, and enable you to eliminate your costly leased lines and avoid expensive time consuming fiber trenching.
Wireless WAN Applications
Wireless WAN applications are endless for Trango long-range wireless Ethernet bridges. For example, a business may need to link its IT infrastructure to a few outlying buildings; a university or any school may need to provide internet access to dormitories or other buildings across campus; or a hospital may need to establish a secure link to a clinic across town so that doctors may securely exchange patient information over a high-speed connection.
Whether you need to a network connection across the street, across town, or from urban to rural areas, Trango wireless WAN/LAN building-to-building outdoor networks are ideal for any private enterprise or network operator that requires high-speed connectivity between two or more remote locations. Trango long range wireless wide area network (WWAN) solutions are well suited for a wide variety of industries and applications because they deliver high-capacity bandwidth, are extremely reliable, highly secure, and can be established with minimal effort and cost.
Licensed Point-to-Point Wireless WAN Radios
* TrangoLINK Giga® is a split-architecture (ODU/IDU) full duplex RF microwave system link that is both native Ethernet and native-TDM.
* TrangoLINK® Apex is an all-outdoor full duplex RF microwave radio that is native-Ethernet for 100% IP traffic.
* ATLAS 4900™ is an all-outdoor native Ethernet OFDM 4.9 GHz wireless bridge that operates in the licensed Public Safety band.
Unlicensed Point-to-Point Wireless WAN Radios
* TrangoLINK-45™ is an all-outdoor, native Ethernet, multi-band OFDM wireless Ethernet bridge that is capable of operation in 4 different 5 GHz bands (5.2, 5.3, 5.4, 5.8 GHz).
* TrangoLINK-10™ is an all-outdoor, native Ethernet 5.8 GHz wireless bridge.
Unlicensed Point-to-MultiPoint Wireless WAN Radios
For delivering point-to-multipoint (PtMP) broadband access wireless WAN connectivity from a central office to many remote offices, Trango offers these robust solutions.
* Access5830™ System 5.8 GHz broadband wireless access system delivers up to 10 Mbps up to 18 miles.
* Trango M2400S™ 2.4 GHz broadband wireless access system delivers up to 5 Mbps up to 25 miles.
* Trango M900S™ 900 MHz broadband wireless access system delivers up to 3 Mbps up to 20 miles.
outdoor wireless Ethernet connections
Trango's long range fixed wireless broadband Ethernet equipment is ideal for all types of wireless wide area network (WWAN) and wireless local area network (WLAN) applications. Trango outdoor wireless networking solutions allow you to quickly, easily, and cost effectively deploy reliable, high-speed, secure wireless IP connections between multiple remote locations at distances up to 45+ miles, and enable you to eliminate your costly leased lines and avoid expensive time consuming fiber trenching.
Wireless WAN Applications
Wireless WAN applications are endless for Trango long-range wireless Ethernet bridges. For example, a business may need to link its IT infrastructure to a few outlying buildings; a university or any school may need to provide internet access to dormitories or other buildings across campus; or a hospital may need to establish a secure link to a clinic across town so that doctors may securely exchange patient information over a high-speed connection.
Whether you need to a network connection across the street, across town, or from urban to rural areas, Trango wireless WAN/LAN building-to-building outdoor networks are ideal for any private enterprise or network operator that requires high-speed connectivity between two or more remote locations. Trango long range wireless wide area network (WWAN) solutions are well suited for a wide variety of industries and applications because they deliver high-capacity bandwidth, are extremely reliable, highly secure, and can be established with minimal effort and cost.
Licensed Point-to-Point Wireless WAN Radios
* TrangoLINK Giga® is a split-architecture (ODU/IDU) full duplex RF microwave system link that is both native Ethernet and native-TDM.
* TrangoLINK® Apex is an all-outdoor full duplex RF microwave radio that is native-Ethernet for 100% IP traffic.
* ATLAS 4900™ is an all-outdoor native Ethernet OFDM 4.9 GHz wireless bridge that operates in the licensed Public Safety band.
Unlicensed Point-to-Point Wireless WAN Radios
* TrangoLINK-45™ is an all-outdoor, native Ethernet, multi-band OFDM wireless Ethernet bridge that is capable of operation in 4 different 5 GHz bands (5.2, 5.3, 5.4, 5.8 GHz).
* TrangoLINK-10™ is an all-outdoor, native Ethernet 5.8 GHz wireless bridge.
Unlicensed Point-to-MultiPoint Wireless WAN Radios
For delivering point-to-multipoint (PtMP) broadband access wireless WAN connectivity from a central office to many remote offices, Trango offers these robust solutions.
* Access5830™ System 5.8 GHz broadband wireless access system delivers up to 10 Mbps up to 18 miles.
* Trango M2400S™ 2.4 GHz broadband wireless access system delivers up to 5 Mbps up to 25 miles.
* Trango M900S™ 900 MHz broadband wireless access system delivers up to 3 Mbps up to 20 miles.
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