Abstract: An object of the invention is to provide a diversity receiver and a reception system switching method capable of controlling diversity reception start and stop according to the switch condition responsive to person's liking and the use environment. An input section (109) allows the user to select and specify any of a diversity reception mode using two reception channels at all times, a single reception mode using a single reception channel at all times, or an automatic control reception mode for switching between the diversity reception and the single reception in response to the reception state of each mode, and a control section (107) determines a switching determination condition used in the automatic control reception mode according to mode selection information of other two modes.

Abstract: It is a theme of the present invention to provide a diversity receiving device and a diversity receiving method capable of making a diversity start not to cause receiving errors and also improving a sensitivity. There is a difference in a jamming wave level that is allowed to get the same received quality between the diversity reception and the single branch reception, so that a gain improving effect equivalent to a diversity gain is expected by the diversity reception in contrast to the single branch reception. Therefore, a dynamic range of the jamming wave from a transmitting portion (105) of a second radio system in a radio terminal is set smaller in expectation of the improving effect of such jamming wave resistance, and then a transmission control signal (S117) is acquired from a transmission signal controlling portion (106). Thus, the diversity reception is started before a start of transmission, and diversity control is applied adaptively without deterioration of the received quality.

Abstract: The objective of the present invention is to provide a diversity receiver that detects differences in reception qualities for reception branches, and that controls the starting and halting of a diversity operation in accordance with the difference in the reception qualities, so that power saving is enabled and battery operating periods can be extended. A difference in reception levels (A, B) which are reception qualities for reception branches (13a, 13b), is employed to determine whether desired diversity effects are available or not. In a case wherein it is determined that desired diversity effects are not available, the diversity operation is halted and the supply of power to a reception branch that is not to be used is halted, and the combining operation is also halted.

Abstract: A subject of the present invention is to provide a receiver and a communication terminal that are adapted appropriately for a plurality of communication systems.