Abstract: A communication method applied to an communication device comprising M first type antenna following a first communication standard and N second type antennas following a second communication standard, M and N are positive integers. The communication method comprises: (a) measuring usage time of the second type antennas; and (b) controlling a number of the antennas that the communication device use according to the usage time of the second type antennas.

Abstract: An FSK modulating apparatus includes a first phase locked loop arrangement having a first voltage controlled oscillator for generating a space frequency signal of a modulation signal and a second phase locked loop arrangement having a second voltage controlled oscillator for generating a mark frequency signal of the modulation signal. The apparatus also includes a third voltage controlled oscillator used to produce an FSK modulated output signal. After input data changes frequency to a space frequency or a mark frequency, a control voltage for the phase locked loop arrangement that is associated with the resulting frequency is routed through a low pass filter having a flat group delay characteristic to the third voltage controlled oscillator. After a set period of time has elapsed, the third voltage controlled oscillator replaces the voltage controlled oscillator of the particular phase locked loop arrangement associated with the current state of the modulator signal.

Abstract: A gain control circuit for a radio transmitter, such as the radio transmitter portion of a radiotelephone operative to transmit a .pi./4 DQPSK-modulated signal in discrete bursts. The signal portion of the signal transmitted during each discrete burst forms a slot and at least one of the slots includes a pre-determined data sequence portion. The peak power level of the portion of the slot comprising the pre-determined data sequence portion, once amplified by amplifier circuitry of the radiotelephone, is compared with a stored value representative of the peak power level of a corresponding portion of a slot amplified to be of a desired signal level. Responsive to such comparison, the amplification level of the amplifier circuitry is altered.