Abstract: The present invention relates to a phase lock oscillator which has a phase-locked loop including a reactive element and varies a reactance of the reactive element at an instant prior to an instant at which the phase-locked loop reaches a limit of maintaining its lock state, and relates to a communication equipment with the lock phase oscillator mounted therein. The phase lock oscillator and the communication equipment can flexibly adapt to variances in environment conditions and maintain stable and high service quality.

Abstract: A portable mobile terminal or a transmission unit, applicable to multiplex radiocommunication systems including a CDMA, comprises a modulating section for modulating a transmission signal by using a spectrum spread system, an amplifying section for amplifying the modulated transmission signal to a needed transmission power, a plurality of variable gain units provided between the modulating section and the amplifying section to be connected in series to each other to provide an ability of changing a gain of the transmission signal modulated by the modulating section, and respectively having gain-to-phase characteristics set to cancel a phase variation of the transmission signal to the entire gain variation, and a control section for controlling a gain of each of the variable gain units. The portable mobile terminal and the transmission unit can control the transmission power in multistage throughout a wide range, and can minimize the phase variation of the transmission signal at that time.

Abstract: The present invention relates to a phase lock oscillator which has a phase-locked loop including a reactive element and varies a reactance of the reactive element at an instant prior to an instant at which the phase-locked loop reaches a limit of maintaining its lock state, and relates to a communication equipment with the lock phase oscillator mounted therein. The phase lock oscillator and the communication equipment can flexibly adapt to variances in environment conditions and maintain stable and high service quality.

Abstract: In a radio paging receiver which is for receiving call signals and which includes a control section (5) for making each of a PLL synthesizer section (4), a frequency converter section (2), and a demodulator section (3) carry out intermittent operation selectively in a short intermittent operation cycle synchronized with the call signals and in a long intermittent operation cycle longer than the short intermittent operation cycle, the PLL synthesizer has first and second loop filters (7 and 8) having first and second time constants, respectively. The second time constant is larger than the first time constant. One of the first and the second loop filters is selectively operable at a time.

Abstract: A radio selective calling receiver having at least two, i.e., a first and a second, local oscillators constituted by respective synthesizers. The oscillation frequencies of the local oscillator are controlled by the apparatus including a frequency calculator for executing frequency calculations according to the received call signal frequency and the oscillation frequencies of the first and second local oscillators so that harmonics of either one of the oscillation frequencies are not interference frequencies to the other oscillation frequency or the received signal frequency.

Abstract: In a radio receiver a PLL oscillator generates a phase locked oscillation signal with a controllable frequency and a frequency multiplier multiplies the controllable frequency with a controllable factor into a local oscillation frequency to provide a local oscillation signal for mixing into an IF signal with a radio signal reaching the receiver, the IF signal is monitored to raise the controllable frequency and to reduce the controllable factor when a spurious signal coexists with the radio signal. This coexistence is detected by monitoring a level difference between the IF signal and an output signal of an IF filter. Preferably, the oscillator comprises in a PLL two VCO's for generating phase locked oscillation signals of higher and lower oscillation frequencies, such as 260 and 65 MHz, and a controllable prescaler supplied with high and low voltage signals when the VCO's are put in operation at the higher and the lower oscillation frequencies.