GMSK Packet Data Modem and RF Transceiver
CMX990
In circumstances where it is required to have a higher performance regarding intermodulation products
(for instance to meet ETS 300 113) or to save some current that results from the use of an image reject
mixer, it is possible to bypass the receiver front end completely and power these down. In this case the
front end functions can be carried out using external components. The transmit mixer divide by two
function should be disabled in this case and the VCO would operate at half the frequency.
Figure 21 Simplified Block Diagram of CMX990 Showing Example Frequency
Plan for 864-870MHz (Rx) / 819-825MHz (Tx) band
ã 2004 CML Microsystems Plc
61
D/990/1
CMLMICRO [ CML MICROCIRCUITS ]
