RF modem utilizing SAW device and pulse shaping

A modem and surface acoustic wave technology, applied in power oscillators, shaping networks in transmitters/receivers, amplitude modulation carrier systems, etc., can solve the problems of noise, low spectral density of transmitted signals, etc., and achieve lower production costs and cheaper packaging. , the effect of increasing production

Inactive Publication Date: 2005-02-09
射频波有限责任公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The transmitted signal has low spectral density, and to a receiver without this code sequence, it appears as noise

Method used

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  • RF modem utilizing SAW device and pulse shaping
  • RF modem utilizing SAW device and pulse shaping
  • RF modem utilizing SAW device and pulse shaping

Examples

Experimental program
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no. 1 example

[0097] figure 1 Shows a block diagram of an RF modem constructed according to the first embodiment of the present invention. The RF modem generally indicated by the reference number 10 includes a transmitting circuit system and a receiving circuit system. A part of the modem, the surface acoustic wave correlator, is shared by the transmitter and receiver.

[0098] The constructed RF modem 10 operates as a pulse transmitter and a pulse receiver. In the sense that it can be universally used in many different types of data communication systems, it is versatile, and several examples will be described below. The RF modem can be used as a physical layer (PHY) in a layered communication system such as the ISO OSI communication stack.

[0099] For example, the pulse transceiver RF modem 10 can be used to construct different types of communication systems, such as on-off keying (OOK), pulse width modulation (PWM), pulse position modulation (PPM) or other types of pulse modulation. Pleas...

no. 3 example

[0227] In order to achieve a higher communication bit rate, other correlators and related circuit systems can be added to the first and second modem embodiments described above. Generally, any number of correlators can be attached, where f is used i The correlation function or code of each correlator represented by (t) is orthogonal to the correlation functions of all other correlators. When the correlation functions (ie codes) of the correlators are orthogonal to each other, each correlator transmits and receives independently of other correlators. However, a sufficient number of correlation functions must be established that satisfy the following criteria.

[0228] i (t), f j (t)>=0, when all i≠j (5)

[0229] In other words, the cross-correlation between all codes must be very low, that is, about 0. For example, those skilled in the art can easily generate a plurality of linear FM codes that are substantially orthogonal to each other and whose cross-correlation is close to zero....

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Abstract

A bidirectional direct sequence spread spectrum half-duplex RF modem which can be applied to transmit and receive numerous types of analog and digital pulse modulation. The modem incorporates two different SAW devices fabricated on a single monolithic substrate. A first SAW device is used as a resonator in the oscillator circuit while a second SAW device is used as the correlator for transmit and receive operations. The RF modem operates as an analog or digital pulse transmitter and receiver and is adapted to be generic and versatile enough to be used in many different types of data communication systems, such as OOK, PWM and PPM. The RF modem can be used as the physical (PHY) layer in a layered communication system such as the ISO OSI communication stack. In an alternative embodiment, the transmission bit rate is increased using a plurality of correlators wherein each is configured with a unique function (i.e., code) that is orthogonal with all other functions.

Description

Technical field [0001] The present invention generally relates to a radio frequency (RF) modem, and more specifically, the present invention relates to a surface acoustic wave-based spread spectrum RF modem that introduces an up-conversion circuit and a pulse shaping circuit to limit the frequency output of a transmitted signal. Background technique [0002] With the rapid growth of computer usage, the demand for peripheral devices and systems connected via wireless connections is also increasing. Currently, the number of wireless applications is increasing rapidly in areas such as security alarms, networking, data communications, telephone technology, and computer security. [0003] Currently, there are many ways that wireless communication can be used, such as ultrasonic, IR, and RF. The communication technology commonly used in RF wireless communication is spread spectrum technology. Spread spectrum communication is a communication technology in which signals are transmitted b...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H04B1/707H04B1/7093H04L7/04H04L25/03H04L25/06H04L25/49H04L27/02
CPCH04L27/02H04L25/03834H04L25/4902H04B1/7093H04B1/70712H04L7/043H04L25/06H04W92/02
Inventor 戴维·本·巴萨特摩西·勒纳
Owner 射频波有限责任公司
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