JPS60121831A - Diversity receiver - Google Patents

Abstract

PURPOSE:To constitute an inexpensive, small-sized receiver with low power consumption by holding a signal corresponding to the intensity of an electric field, and comparing the intensity of the electric field of every antenna with a current flowing to a capacitor after antenna switching. CONSTITUTION:An arrival radio wave is received by both receiving antennas 11 and 12, amplified respectively, and passed through a switch 15 to perform envelope detection by frequency conversion and amplification, etc., and a comparator 18 compares it with a reference voltage to detect the arrival of the radio wave. A control part 19 makes an intensity comparison between the electric fields of the antennas 11 and 12 by a comparator and the switching of the switch 15 according to the radio wave arrival detection signal to select an antenna having higher electric field intensity. Information from a frequency discriminator 21 for detecting the output of a receiver 16 is outputted to the control part 19, and decoded and outputted. Thus, only one reception part is used by the switching of the switch 15, so the constitution is simplified and the power consumption is also small.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a diversity receiver for a security system, etc., which communicates between a detector and a main body using radio waves.

Conventional configuration and its problems Traditionally, when receiving weak radio waves, there are two ways to prevent signal loss caused by interference such as reflected waves, that is, a drop in received signal strength. A diversity receiver is used.

In particular, high reliability is required for the transmission of security-related information.

Hereinafter, a conventional flexible receiver used for this purpose will be explained with reference to all the drawings.

FIG. 1 is a block diagram showing a conventional receiver and its transmitter.

In FIG. 1, a transmitter 1 drives a transmitting antenna 2 and radiates radio waves modulated with security information. These radio waves are simultaneously received by antennas 3 and 4 in the receiver, and are subjected to amplification, frequency conversion, filtering, etc. in receiving sections 6 and 6, respectively, and output a received signal. The strength of the received signals from these two sources is compared by the comparing section 7, and the switch 8
The larger signal is selected and demodulated by the demodulator 9, and the information is decoded and outputted by the decoder 10. The output is used to display information and control equipment.

In the receiver configured as described above, the switch 8 selects the larger signal received by the antennas 3 and 4, but since the antennas 3 and 4 are installed at a distance, the two The probability that the received signals will drop at the same time is very small, allowing highly reliable reception.

However, in the configuration described in ``2'', two sets of receivers are required, and these receivers have five or six complex circuits, which not only makes the device expensive, but also increases the size of the device. It also had drawbacks such as requiring a large amount of power and also being prone to generating switch noise due to switching.

Purpose of the Invention The present invention solves the following drawbacks of the conventional technology.
The purpose of the present invention is to provide a low-cost, small-sized, low-power-consumption Guibanchii receiver.

Composition of the Invention In order to achieve the above object, the present invention comprises at least two or more antennas, a receiving section that receives, amplifies and detects radio waves entering the antenna, and is provided between the 111 anti and the receiving section; a switch that electrically connects the only antenna and the receiver by converting it into a capacitor; It has a discharge circuit that discharges a discharge, a current detection circuit that detects the current flowing in the capacitor 1, and a control section that controls switching of the switch r'i fl according to a detection signal from the current detection circuit 1, and an off record. The control section determines the current value of the capacitor sequentially held in the peak hold circuit by sequentially switching the electrical coupling between the receiving section and each antenna, and compares the strength of the electric field entering each of the antennas to determine the received electric field. This is so that only one antenna with a strong strength is selected for reception.

DESCRIPTION OF EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings.

FIG. 2 is a block diagram of a diver/chii receiver in one embodiment of the present invention.

In FIG. 2, reference numerals 11 and 12 are receiving antennas, which both receive incoming radio waves, are amplified by preamplifiers 13 and 14, respectively, and are subjected to frequency conversion, amplification, etc. in a receiving section 16 via a switch 15. 1T is a wave detector that performs saturation line detection, and compares the detected signal with the base 11 (potential) in a comparator 18 to detect the arrival of radio waves. 1911.l: A control unit that detects the radio waves of the comparator In response to the arrival detection signal, the antennas 11 and 12 are switched by the comparator 20 and the switch 1509J.
Compare the electric field strength at , and select the antenna with the strongest electric field.

21 is a frequency discriminator that detects the output of the receiving section 16, and outputs the information to the control section 19, which decodes and outputs the information.

Next, the configuration of the comparison section 20 will be explained in more detail.

FIG. 3 shows the comparator 20 in more detail.] In the lock diagram, the detector υ'' of the detector 17 is supplied to the base of the Sould circuit. First, the transistor switch 20d is controlled via the resistor 20C to discharge the charge in the capacitor 20b.

Furthermore, the capacitor 2 flowing through the transistor 20a
The charging current to 0b is connected to transistor 20e and resistor 2Of.
is detected and output to the control section 19.

FIG. 4 is a timing chart of the above configuration.

In FIG. 4, waveform 9 indicates the arrival of filtering;
It shows the timing to receive ife. Waveforms C and d
Depending on the strength of the electric field received by the antennas 11 and 12, the waveform d1, that is, the electric field received by the antenna 2 will be stronger. The waveform e indicates the position of the switch 15, and indicates that the antenna 11 is selected when the level is high, and the antenna 12 is selected when the level is low. The waveform (■) is the output of the wave detector 17 and corresponds to the strength of the electric field at the antenna selected by the switch 15. Waveform e' shows an enlarged view of switch 16 at position C. With the waveform q applied to the base of transistor switch 20d, transistor switch 20d closes during the second half of the period when antenna 12 is selected. The waveform indicates the voltage applied to the capacitor 20b, and the maximum value of the output waveform f of the detector 17 is held. However, if the transistor switch 20d is closed, it becomes zero. Waveform i shows the charging current flowing to capacitor 20b via transistor 20a, which flows when the output of detector 17 becomes larger than the held value. This current is detected by the transistor 20e and outputted to the control section 19. The potential of the collector of the I transistor 20e is shown by a waveform jK. T at charging current 1
The period indicated by is immediately after switching between antennas, and the maximum value while antenna 11 was selected is held in capacitor 2ob, but since the electric field of antenna 12 is larger than that of antenna 11, A charging current flows to the capacitor 20b between +QJ and T. On the other hand, when the electric field strengths of antenna 11 and antenna 12 are reversed, capacitor 2
The potential of 0b and the charging current are shown in the waveform by 1. In this case, at period 1rMJ T, the detector 17
Since the output of the battery becomes small, no charging current flows. Therefore, the collector potential of the transistor 20e between 191 and T becomes zero. The control unit 19 controls the antenna 11 based on the collector potential of the transistor 20e between JtJI.
The electric field strengths of and 12 can be compared.

As described above, in this embodiment, the part for comparing the electric fields of the antenna can be constructed from a very simple circuit. Moreover, since the same transistor and capacitor are used for comparison of signal magnitudes, there is almost no effect on the constants of the components, the 6-dimensional characteristics, or the relative softness results, and the device can be constructed using inexpensive components. Furthermore, since the charge in the capacitor 20b is discharged each time, the strength of the electric field can be determined by converting the antenna VJ in one cycle, resulting in a fast response.

Next, a second example of ``Kihitsu'' will be described.

FIG. 6 is a block diagram of a diversity receiver according to a second embodiment of the present invention, which differs from the configuration in FIG. 2 in that the antenna is a four-tree structure. Referring to the drawings below,
- The operation of the above configuration will be explained.

Both of the incoming radio waves are received by the Ushizu antennas 51, 62, 53, 54, and the switch 55 that manipulates them is amplified by the pull-up 56. The frequency is converted 2 and amplified, and the detector 17 performs saturation line detection. The comparator 8 similarly detects the arrival of radio waves.

The comparator 2o has the same configuration, and the information deciphered by the frequency discriminator 21 is also the same.

FIG. 6 is a timing chart similar to that shown in FIG. Waveform m indicates the arrival of radio waves. Waveform n-
: Shows the state of the switch 55, and shows the antenna with the number d selected. Waveform. , p.

q+r indicates the strength of the electric field of the antennas 51, 52, 63, and 54, respectively. The waveform S is the detector 17 at this time.
corresponds to the electric field strength received by each antenna. The waveform t is applied to the base of the transistor switch 20d of the comparator 2o shown in FIG.

The waveform U is the potential of the capacitor 20b, and the waveform shown in FIG.
Similarly, the maximum value of the output waveform S of the wave detector 17 is held. Waveform V is the charging current flowing through transistor 20a. Here, T51°T52, Ta21
T54 is a period indicating the charging current flowing when each antenna is selected. Furthermore, the electric field that the antenna receives is the largest in the antenna in which the current flowed last in the order from period T6 to T54-i, and in the waveform V of FIG. 6, Jg
l 1? jl T 53, that is, the antenna 53. The control unit 19 fixes the three timings T52 to T54 between 191 so that the ill'il best inochi 65 is set to the antenna exhibiting the maximum electric field.

Note that if T52 to T64 are all zero, the antenna 51
Select.

According to the above embodiment, it is possible to quickly compare many antennas without changing the configuration of the comparator 2o, and it is possible to realize an inexpensive receiver with excellent characteristics.

In this embodiment, the comparison section 20 is configured with a peak hold circuit using a capacitor and a transistor, but the comparison section 20
is not limited to capacitors and transistors, but also peak hold circuits using capacitors and diodes, capacitors and FE
Peak hold circuit by T, transistor switch triFET.

It can be realized with a diode, a silice, etc., and a small circuit can also be used, such as a circuit in which the transistor for current detection is coupled at the emitter, or a circuit with increased sensitivity by using more elements.

Amada Seikame 1 part 19 is easy ((Although it can be realized using a microprocessor, etc., it is also easy to implement it using a logic circuit.

As shown in ``Effect of 1 town'', the peak hold circuit using a capacitor holds a value corresponding to the strength of the electric field.
The electric field strength of each antenna is compared by the current flowing into this capacitor after antenna switching, so antennas can be selected quickly with a simple configuration, and with inexpensive parts.
It is possible to create a diversity receiver with excellent temperature characteristics and comparison accuracy, and the effects are significant.

[Brief explanation of the drawing]

Figure 1 is a block diagram of a conventional Diver/Chii receiver;
Figure 3 is a block diagram of a diversity receiver according to an embodiment of the present invention, Figure 3 is a main circuit diagram of the diversity receiver, Figure 4 is a timing chart of the diversity receiver, and Figure 5 is a diagram of the diversity receiver according to the present invention. FIG. 6 is a block diagram of the main parts of the digital receiver according to the second embodiment, and FIG. 6 is a timing chart of four parts of the digital receiver in the second embodiment. 11.12, 51.52, 53.54... Antenna, 13, 14.56... Preamplifier, 16°5
6... Switch, 16... Receiving section, 1
7...Detector, 18...Comparator, 19...
...control section, 2o...-comparison section, 21...
- Frequency discriminator, 20a, 20d. 20 e...Transistor, 20b...
Capacitor, 20C...Resistor. Name of agent: Patent attorney Toshio Nakao and 1 other person No. 1
Figure 2 Output Figure 4 (?) b (6) j Collapse Figure 5 Figure 6

Claims (1)

[Claims] at least two or more antennas; a receiving section that receives and amplifies and detects radio waves entering the antenna;
a switch provided between the receiver and electrically connects the only antenna and the receiver; and a peak bold circuit that holds the strength of the received electric field of the antenna, which is the output of the receiver, in a capacitor. , a discharge circuit for discharging the electric charge of the capacitor, a current detection circuit for detecting a current flowing through the capacitor, and a control section for controlling switching of the switch according to a detection signal from the current detection circuit, and the control section is the received electric field by comparing the electric field strength entering each of the antennas from the current value of the capacitor which is sequentially held in the peak hold circuit by changing the electrical coupling between the receiving section and each antenna (71). Guibanchii receiver is the only one with a strong antenna.