摘要:
A system and method for redirecting data to a mobile device having a long-range RF transceiver and a short-range RF transceiver is provided. The system determines whether th emobile device is in physical proximity to the short-range RF network, and if so, redirects data to the mobile device via the short-range RF network, and if not, redirects data to the mobile device via the long-range RF network. Multiple methods for determining the physical location of the mobile device are provided. Also provided is a short-range RF network including a plurality of RF-enabled interface cradles for generating a network of pico-cells within one or more office locations. As a mobile device comes within th evicinity of one of these pico-cells, contact information is provided to the system indicating the physical location of the mobile device.
摘要:
SAW devices such as interdigital transducers (IDTs) have been widely used in RADAR applications and as filters. An IDT produces a SAW when excited by a single electrical pulse and can be fabricated to embody a code, which code provides for a passive autocorrelation of a SAW input to the IDT and thereby lends itself to further application as a signal generator in a communication device. However, internal dimensions of IDTs are inversely proportional to operating frequency, such that high frequency IDTs present significant manufacturing difficulties. Fabrication of IDTs for high frequency applications is simplified by exploiting a harmonic frequency SAW generated by IDTs. An IDT may therefore be designed according to fundamental frequency internal dimension criteria but can operate at a multiple of the fundamental frequency, thereby providing much higher frequency operation than conventional SAW systems. A communication system based on SAW harmonic techniques would be low-cost, low-power, small and simple alternative to known short range communications schemes, including for example the BIuetooth™ solution. Operation of a second harmonic SAW system at 2.4 GHz based on a fundamental frequency of 1.2 GHz is contemplated.
摘要:
A system and method for redirecting data to a mobile device having a long-range RF transceiver and a short-range RF transceiver is provided. The system determines whether th emobile device is in physical proximity to the short-range RF network, and if so, redirects data to the mobile device via the short-range RF network, and if not, redirects data to the mobile device via the long-range RF network. Multiple methods for determining the physical location of the mobile device are provided. Also provided is a short-range RF network including a plurality of RF-enabled interface cradles for generating a network of pico-cells within one or more office locations. As a mobile device comes within th evicinity of one of these pico-cells, contact information is provided to the system indicating the physical location of the mobile device.
摘要:
SAW devices such as interdigital transducers (IDTs) have been widely used in RADAR applications and as filters. An IDT produces a SAW when excited by a single electrical pulse and can be fabricated to embody a code, which code provides for a passive autocorrelation of a SAW input to the IDT and thereby lends itself to further application as a signal generator in a communication device. However, conventional SAW expanders and compressors typically have insertion losses greater than 20 dB, which can have a profound effect on an RF link budget in a communication system. Insertion losses are drastically reduced by using a single phase unidirectional transducer (SPUDT-type) instead of a conventional IDT as a SAW expander/compressor. A SPUDT-type reflects SAW components which are lost in conventional IDT designs so that a stronger SAW is directed toward a transmission element. In a receiver, a SPUDT-type directs a stronger SAW toward a compressor IDT. A communication system based on SPUDT-type techniques would be low-cost, low-power, small and simple alternative to known short range communications schemes, including for example the Bluetooth™ solution. Operation of a SAW system at a frequency of 2.4 GHz is contemplated.
摘要:
SAW devices such as interdigital transducers (IDTs) have been widely used in RADAR applications and as filters. An IDT produces a SAW when excited by a single electrical pulse and can be fabricated to embody a code, which code provides for a passive autocorrelation of a SAW input to the IDT and thereby lends itself to further application as a signal generator in a communication device. However, conventional SAW expanders and compressors typically have insertion losses greater than 20 dB, which can have a profound effect on an RF link budget in a communication system. Insertion losses are drastically reduced by using a single phase unidirectional transducer (SPUDT-type) instead of a conventional IDT as a SAW expander/compressor. A SPUDT-type reflects SAW components which are lost in conventional IDT designs so that a stronger SAW is directed toward a transmission element. In a receiver, a SPUDT-type directs a stronger SAW toward a compressor IDT. A communication system based on SPUDT-type techniques would be low-cost, low-power, small and simple alternative to known short range communications schemes, including for example the Bluetooth TM solution. Operation of a SAW system at a frequency of 2.4 GHz is contemplated.
摘要:
An adaptive tuning method for a wireless communication device determines the impedance of a matching circuit relative to an impedance to be matched and adjusts the impedance of the matching circuit accordingly. A passive surface acoustic wave (SAW) device includes multiple terminated interdigital transducers (IDTs) which generate reflected SAWs when excited by incident SAWs, each reflected SAW having magnitude and phase characteristics dependent upon the particular IDT termination. According to the invention, the IDT terminations include the impedance matching circuit and the impedance to be matched. Input IDTs in the SAW device are excited with electrical signals, which are converted to generate the incident SAWs. The resultant reflected SAWs are converted by output IDTs into output electrical signal signals which can then be analyzed to determine magnitude and phase differences between the output electrical signal signals and generate an impedance matching circuit control signal based thereon.