| 摘要 |
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. |
