200 meters remote control schematic design
Posted on Dec 11, 2010 5043
Early transmitters use more LC oscillator frequency drift is more serious. SAW devices appear to solve this problem, the frequency stability of the crystal substantially the sa
me, and its fundamental frequency of up to hundreds of megabytes or even gigahertz. Without octave, compared with the crystal oscillator circuit is extremely simple. The following two circuits for the common transmitter circuit, due to the use of SAW devices, the circuit is very stable, even when grasping the antenna, acoustic, or other parts of the circuit, the transmit frequency will not drift. And a compared with Figure II transmission power larger. Up to 200 meters. ICRF002 ceramic resonator and replace it with a different resonators, the reception frequency can cover 300-440MHz. MICRF002 has two operating modes: scan mode and fixed mode. Scan mode accepts bandwidth of up to several hundred KHz, this mode is mainly used for the LC oscillator and transmitter supporting the use, because, LC transmitter frequency drift is large, in the scan mode, the data communication rate of 2.5KBytes per second. Fixed bandwidth mode only tens of KHz, this mode is used and the use of the crystal frequency stabilization transmitter supporting data rates up to every second 10KBytes. The operating mode is selected by MICRF002 16 feet (SWEN) implementation. In addition, the wake-up function can wake up decoder or CPU, in order to minimize power consumption. After MICRF002 is complete monolithic superheterodyne receiver circuit, the basic realization of the antenna input data directly, receiving distance is generally 200 meters.