摘要:
It is an object of the present invention to switch bands with a simple structure in which frequency bands can be individually switched respectively in a transmission and a reception and only a receiving part can be switched to another frequency band without disconnecting an upward line during communication.The device of the invention includes an antenna (1) capable of transmitting and receiving radio waves of first and second frequency bands, a wave separator (2), antenna sharing devices (3A, 3B) respectively provided so as to correspond to the frequency bands, transmitting circuits (4A, 4B), transmitting PLL synthesizers (5A, 5B), receiving circuits (6A, 6B) and receiving PLL synthesizers (7A, 7B). A control part 102 controls, through a common three-line serial bus, the transmitting PLL synthesizers (5A, 5B), the receiving PLL synthesizers (7A, 7B), a transmitting band switching signal generating circuit (8) and a receiving band switching signal generating circuit (9) to individually switch the frequency bands respectively in the transmission and the reception.
摘要:
It is an object of the present invention to switch bands with a simple structure in which frequency bands can be individually switched respectively in a transmission and a reception and only a receiving part can be switched to another frequency band without disconnecting an upward line during communication. The device of the invention includes an antenna (1) capable of transmitting and receiving radio waves of first and second frequency bands, a wave separator (2), antenna sharing devices (3A, 3B) respectively provided so as to correspond to the frequency bands, transmitting circuits (4A, 4B), transmitting PLL synthesizers (5A, 5B), receiving circuits (6A, 6B) and receiving PLL synthesizers (7A, 7B). A control part 102 controls, through a common three-line serial bus, the transmitting PLL synthesizers (5A, 5B), the receiving PLL synthesizers (7A, 7B), a transmitting band switching signal generating circuit (8) and a receiving band switching signal generating circuit (9) to individually switch the frequency bands respectively in the transmission and the reception.
摘要:
It is an object of the present invention to suppress an abrupt gain change and smoothly and highly accurately control transmitted electric power even if the transmitted electric power greatly changes when a closed loop control that crosses the threshold value as the detection limit of the transmitted electric power.The transmitted electric power of a self-station is detected to obtain an error between the detected transmitted electric power of the self-station and transmitted electric power set in accordance with a transmitted electric power control bit sent to the self-station from the other station. A buffer unit such as a transmitted electric power deciding part, an error integrating part or the like is provided for preventing the obtained error from greatly changing upon great change of the transmitted electric power when the transmitted electric power is controlled by crossing the threshold value as the detection limit of the transmitted electric power. Thus, an error when the gain of the variable gain amplifier is suppressed.
摘要:
It is an object of the present invention to suppress an abrupt gain change and smoothly and highly accurately control transmitted electric power even if the transmitted electric power greatly changes when a closed loop control that crosses the threshold value as the detection limit of the transmitted electric power. The transmitted electric power of a self-station is detected to obtain an error between the detected transmitted electric power of the self-station and transmitted electric power set in accordance with a transmitted electric power control bit sent to the self-station from the other station. A buffer unit such as a transmitted electric power deciding part, an error integrating part or the like is provided for preventing the obtained error from greatly changing upon great change of the transmitted electric power when the transmitted electric power is controlled by crossing the threshold value as the detection limit of the transmitted electric power. Thus, an error when the gain of the variable gain amplifier is suppressed.
摘要:
A determining section (18) and gain variation amount detecting section (9) detect a period having a possibility of a DC-component offset in an internal circuit of a direct conversion receiver increasing beyond an allowable value due to AGC operation, and during the period, a cut-off frequency of each of high-pass filters (12a to 12d) is set at a frequency higher than that in general operation, thereby rapidly converging transient responses of signals passed through the high-pass filters, while controlling precisely operation timings of reception power measuring section (16), gain calculating section (22), gain control section (23) and circuit power supply control section (24) composing an AGC loop, whereby the DC offset is prevented from increasing and stable circuit operation is assured. It is thereby possible to achieve further reductions in size and power consumption of a CDMA receiver using the direct conversion receiver.
摘要:
A handy image data filing apparatus is disclosed, which is made up of a hand scanner as an image data reading device and an IC memory card as an image data storing medium. Image data on an object such as a name card is read by the hand scanner, and filed into the IC memory card. The read data is stored into the IC memory card, together with ID data for identifying the image data to be stored. The ID data is used for retrieving the image data later, and is entered from a keyboard. For retrieval, ID data corresponding to the desired image data is entered from the keyboard. The image data is specified by the ID data entered, and displayed by a liquid crystal display device.
摘要:
A fluoran compound represented by general formula: ##STR1## where each of R.sub.1 and R.sub.2 is a C.sub.1 -C.sub.4 alkyl group, a cycloalkyl group or an aryl group, or R.sub.1 and R.sub.2 may form together with N a saturated ring, R.sub.3 is a benzyl or phenyl group which may be substituted, and R.sub.4 is a C.sub.1 -C.sub.4 alkyl group.
摘要:
An antenna selection diversity apparatus capable of shortening, when antennas are switched in frame units, a measuring time of antennas and shortening the time of selecting an optimal antenna from among a plurality of antennas on standby. In this apparatus, an antenna selection section (109) selects one of three antennas as an antenna in actual use for a period of a plurality of frames consecutively according to selection priority stored in an antenna information storage section (108) and gives an instruction for selecting one of two antennas on standby as an antenna to be measured once at a period of a plurality of frames to an antenna selection switch (104). When the reception level of the antenna in actual use measured by a reception level measuring section (107) falls below the reception level of the antenna to be measured a predetermined number of times consecutively, the antenna selection section (109) gives an instruction for selecting the antenna to be measured as the antenna in actual use to the antenna selection switch (104).
摘要:
A transmission electric power control device includes: a coupler 12, detector 13, electric power amplifier 14, error detection means 15, target value generation means 16, gain variable means 17, control calculation means 18, control calculation parameter generation means 19, modulator 20, control variable addition means 21, transmission electric power control means 22, and transmission electric power designation means 23. In this case, the automatic transmission electric power control feedback loop includes: the coupler 12, detector 13, error detection means 15, control calculation means 18, control calculation parameter generation means 19, transmission electric power designation means 23, control variable addition means 21 and gain variable means 17. When the control calculation parameter in the automatic transmission electric power control feedback loop is made variable according to the transmission electric power designation information and also when the convergence offset value of the loop response characteristic is made variable, it is possible to conduct an electric power control of a high dynamic range, high linearity and high accuracy even if the electric power source control of the electric amplifier is conducted for each transmission electric power and the gate bias control is conducted.
摘要:
A power amplifier has an input terminal; an output terminal; an N number of bypassable amplification circuits which are connected directly or indirectly in a sequential manner between the input terminal and the output terminal; an impedance conversion circuit which is connected directly or indirectly between the amplification circuit of a final stage and the output terminal; and a bias control circuit which controls the amplification circuits, each of the amplification circuits is configured by a high-frequency switch circuit, and an amplifier which is connected directly or indirectly to the switch circuit, and the bias control circuit controls power source voltages of the amplifiers and controls status of the switch circuit.