JPH0681069B2 - Transceiver with antenna failure detection function - Google Patents

Description

TECHNICAL FIELD The present invention relates to a transceiver that performs diversity reception.

In particular, it relates to a transceiver having a function of detecting a failure of an antenna using a receiver and switching a transmission output to a normal antenna.

[Prior Art] Conventionally, a transmission / reception device that performs diversity reception has been provided with one antenna that shares transmission and reception and an antenna for auxiliary diversity reception. Therefore, when the transmitting / receiving antenna fails, the auxiliary diversity receiving antenna can be used for reception.

In addition, the base station that enhances reliability was manually switched.

[Problems to be Solved] In the above-described conventional diversity transmitter / receiver, in addition to the antenna for sharing transmission / reception, only an antenna for auxiliary diversity reception is provided, so that the antenna for transmission / reception fails Had a problem that it could receive but could not send.

Moreover, since the system is manually switched, it takes time to detect an abnormality of the antenna, and there is a problem that communication cannot be performed during that time.

The present invention has been made in view of the above problems, and when one antenna for both transmission and reception fails, it is automatically detected and switched to another antenna for both transmission and reception to ensure communication. It is an object of the present invention to provide a transmitter / receiver with an antenna failure detection function capable of performing the above.

[Means for Solving the Problems] In order to achieve the above object, a transceiver with an antenna failure detection function of the present invention includes a plurality of antennas for both transmission and reception, and transmission for selecting one of these antennas as an antenna for transmission. A changeover switch, a plurality of receivers for outputting a DC voltage corresponding to each input electric field of the antenna as an analog signal, and an A / D converter for converting an analog signal from these receivers into a digital signal, A digital signal indicating a DC voltage level corresponding to the input electric field converted by the A / D converter is sampled, and the input electric field of the antenna is measured for a certain period of time so as to avoid the influence of a change in the instantaneous electric field due to Rayleigh fading. When the difference between the measured values of the antennas exceeds a predetermined value, the transmission is performed so that the antenna with the largest input electric field is selected. And a control unit for operating the changeover switch.

[Embodiment] An embodiment of a transceiver with an antenna failure detection function according to the present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram of the embodiment.

In the figure, 1a and 1b are antennas for both transmission and reception. The high frequency signals input to the antennas 1a and 1b pass through the receiving BPFs 2a and 2b and are input to the receivers 3a and 3b, respectively. The demodulated outputs of the receivers 3a and 3b are DC voltage (RSSI) according to the input electric field of the antennas 1a and 1b.
Is omitted) is output to the comparator 4. The comparator 4 operates the reception demodulation changeover switch 5 to select and output the demodulation output having the larger input electric field.

Further, the RSSIs of the receivers 3a and 3b are also input to the control unit 6. The control unit 6 has two sets of A / Ds that convert the analog signals RSSI output by the receivers 3a and 3b into digital signals.
The converter and the digital signal converted by the A / D converter are sampled, and RSS of the receivers 3a and 3b is sampled for a certain period of time.
If the difference in I is detected and if there is a large difference, the transmission changeover switch 7 is operated to switch the output of the transmitter 8 to the normal antenna, and the operation of this CPU is programmed P-. It consists of ROM. Reference numeral 9 is a BPF for transmission.

Note that the control unit 6 measures for a certain period of time in order to prevent the influence of Rayleigh fading, which greatly changes the instantaneous RSSI level when used for mobile communication. . For example, in the case of an instantaneous value with a dynamic range of 30 dB and 40 Hz, the true value drops by as much as 30 dB per second, and the true value cannot be detected when the mobile station is moving. Therefore,
The above-mentioned harmful effects are dealt with by measuring for a certain period of time and taking the average value of the sampled reception electric field levels.

In this way, the present embodiment, in the diversity receiver,
It has a function to measure the input electric field of each antenna 1a, 1b, and by selecting the antenna connected to the transmitter 8 based on the measured electric field value, even if one antenna for both transmission and reception fails Can be automatically detected and switched to another antenna for both transmission and reception to ensure communication.

[Effects of the Invention] As described above, according to the present invention, in a transceiver that performs diversity reception, an antenna abnormality is automatically detected by positively utilizing the reception function, and the transmitter output is switched. The effect is that communication can be secured.

[Brief description of drawings]

 FIG. 1 is a block diagram of an embodiment of the present invention. 1a, 1b: Antennas 2a, 2b: BPF for reception 3a, 3b: Receiver 4: Comparator 5: Reception demodulation selector switch 6: Control section 7: Transmission selector switch 8: Transmitter 9: Transmission BPF

Claims (1)

[Claims] 1. A plurality of transmitting / receiving antennas, a transmission changeover switch for selecting one of these antennas as a transmitting antenna, and a DC voltage corresponding to each input electric field of the antenna as an analog signal. A plurality of receivers that output and an A / D converter that converts analog signals from these receivers into digital signals, and a digital signal that indicates the DC voltage level corresponding to the input electric field converted by this A / D converter. The signal is sampled, the input electric field of the antenna is measured for a certain period of time so as to avoid the influence of the change of the instantaneous electric field due to Rayleigh fading, and when the difference between the measured values of the antennas becomes larger than a predetermined value, the most input electric field is obtained. Antenna failure detection, which comprises a control unit for operating the transmission changeover switch so as to select a large antenna. Function with transceiver.