摘要:
The system for measuring the spillover signal from a transmitter to a receiver in a same frequency repeater or a booster has a frequency conversion device which slightly offsets the transmission frequency from the reception frequency, and a signal detector which measures the offset frequency component in the reception signal. The offset frequency is around 100 Hz, which is higher than the fading frequency, and low enough not to affect the operation of receivers. The measured spillover level is used to control the gain of the repeater, and/or to cancel the spillover signal, so that the repeater has the maximum gain without suffering from oscillation.
摘要:
An input signal is divided equally by a divider and the equally divided outputs are applied to first and second amplifying means, respectively. A filter means, which rejects the fundamental wave component of the input signal but passes therethrough its harmonic component, is connected between the first and second amplifying means. The outputs of the first and second amplifying means are respectively connected to first and second select circuits which select the fundamental wave components of the input signal. The outputs from the first and second circuits are combined in phase with each other, by a combiner, into a composite signal.
摘要:
The performance of an amplifying system is improved by achieving adequate matching. The amplifying system for amplifying signals includes distributing means 1 that distribute a signal, a carrier amplifier 2 that amplifies the distributed first signal in Class AB, a peak amplifier 4 that amplifies the distributed second signal in Class B or Class C, a first transmission line having a given electric length and being connected to an output of the carrier amplifier, a second transmission line having a given electric length and being connected to an output of the peak amplifier, and a combining end 18 for combining an output of the first transmission line and an output of the second transmission line. An impedance of the combining end is differentiated from a parallel impedance of load impedances of the carrier amplifier and the peak amplifier at the maximum power converted respectively by the first transmission line and the second transmission line, or is set as a parallel impedance in which the load impedances of the carrier amplifier and the peak amplifier at the maximum power are changed.
摘要:
To provide a super directional gain in a multi-element array antenna. An array antenna comprising a plurality of antenna elements A-1–A-4 spaced at intervals (equal to or less than a quarter of a wavelength) that provides a supergain is used. A weight generator circuit generates weight data in accordance with phase difference and amplitude difference among the antenna elements A-1–A-4 and directivity data of each of the antenna elements A-1–A-4. The generated weight data is used to weight each of the antenna elements A-1–A-4.
摘要:
In a high sensitive radio receiver system for a diversity reception from two antennae per each of three sectors (SC1, SC3, SC3), a series connection of a bandpass filter (31 to 36) and a low noise amplifier (41 to 46) is contained in each of a plurality of vacuum chambers (81 to 86), the interior of which is cooled by a distinct, separate cooling unit (91 to 96). The two antennae per sector are connected to bandpass filters contained in different vacuum chambers.
摘要:
A mobile communication base station determines the oncoming direction of a radio wave with a simple arrangement and transmits a narrow angle beam in this direction. Received signals from a pair of wide angle beam antennae 21-1 and 21-2 having an equal configuration and a common orientation and which are located close to each other are fed to a direction finder receiver 22 and a communication receiver 15. By utilizing the fact that the both received signals have a coincident amplitude, a phase difference between the received signals is detected. The oncoming direction of the received radio wave (or the direction of a mobile station) is determined on the basis of the phase difference. A beam switcher 12 is controlled so as to connect a transmitter 13 to a narrow angle beam antenna (one of 11-1 to 11-4) which is directed in the oncoming direction thus determined.
摘要:
A receiver directs the center of the main beam of the antenna directivity response in a desired direction by passing signals received by n antenna elements 1a to 1d through a phase shifter 3. An output from the phase shifter 3 is passed through a receiving filter 5 and is then amplified by a low noise amplifier 6 to be delivered as an output. The phase shifter 3 is confined together with the receiving filter 5 and the amplifier 6 in a cryostat 8, and the phase shifter 3 as well as the receiving filter 5 and the amplifier 6 are cooled down by cooling means 9 through a cold stage 9a, whereby the thermal noises generated therein are reduced to a minimum.
摘要:
In a distortion injection path (15) wherein a detected distortion component of a main amplifier (23) becomes amplified, distortion by an auxiliary amplifier (29a) is detected by an auxiliary distortion detector (42) composed of a variable attenuator (27a), a variable phase shifter (28a), a first auxiliary amplifier (29a), a delay line (36) and a phase inverter (37), and the detected distortion is cancelled by an auxiliary distortion canceller (43) composed of a variable attenuator (27b), a variable phase shifter (28a), a second auxiliary amplifier (29b) and a delay line (39), thereby increasing the efficiency of the amplifier.
摘要:
In the balance adjustment using a pilot signal in a distortion detector and a distortion canceller of a feed-forward amplifier for amplifying a CDMA transmission signal, a pilot code is spread by a long code different from that of the CDMA transmission signal to obtain the pilot signal. The pilot signal is converted to a signal of the transmission frequency band, and the converted signal is injected into the transmission signal at the input side of the amplifier. The pilot signal frequency band is detected from the output of an auxiliary amplifier of the distortion canceller and converted to the base band, thereafter being despread to detect the pilot signal (code).
摘要:
A distortion compensation apparatus includes distortion generating means for generating distortions to compensate for a distortion generated in an amplifier 2. The distortion generating means includes a nonlinear circuit 13 having an input/output expansion characteristic as a circuit which generates a distortion of the lowest odd order as a compensation target and also includes a nonlinear circuit 18 having an input/output saturation characteristic as a circuit which generates a distortion of another odd order as a compensation target.