JPH04336817A - Radio receiver - Google Patents

Abstract

PURPOSE:To simultaneously receive two signals in one and the same frequency band without deteriorating the reception sensitivity. CONSTITUTION:Two reception systems are provided on one antenna 10 and a signal switching circuit 78 is interposed between the antenna 10 and at least one of the reception systems. The signal switching circuit 78 is changed over into a through circuit when one signal in a frequency band is received by the one reception system with a switching data from a central processing unit controlling the local oscillation PLL frequency synthesizer 34 (46) of each reception system. Then when two signals in the same frequency band are received simultaneously by the two reception systems, the signal switching circuit 78 is changed over so that the signal is amplified by an amplifier circuit 72 and distributed into two systems by a distribution circuit 74 and they are given respectively to the two reception systems.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a radio receiver equipped with one antenna and a plurality of receiving systems.

0002

[Prior Art] Conventionally, one antenna has been used to transmit two different frequency bands (for example, a 144 MHz band and a 430 MHz band).
Hz band) signals one at a time, and two signals with different frequencies within the same frequency band.
one signal (for example, four as the calling main channel)
A wireless receiver is provided that can simultaneously receive signals of 33.00 MHz and signals of other frequencies within the 430 MHz band.

An example of the structure of this conventional radio receiver will be explained with reference to FIG. In FIG. 4, the signal received by the antenna 10 is split into two, a first filter 12 that passes only the 144 MHz band signal, and a 430 MHz band signal.
A second filter 14 is provided to pass only the band signal. The signal that has passed through the first filter 12 is branched into two after passing through the first switch 16, one of which is given to the first high frequency amplification circuit 18 of the first receiving system, and the other is given to the fourth
The signal is applied to the second high frequency amplification circuit 22 of the second receiving system via the switch 26. Further, the signal that has passed through the second filter 14 is branched into two after passing through the third switch 24.
One of them is given to the second high frequency amplification circuit 22, and the other is given to the first high frequency amplification circuit 18 via the second switch 20. Note that the first and second switches 16 and 20 are interlocked with each other in opposite opening and closing operations, and form a first signal switching circuit 28.
The third and fourth switches 24 and 26 similarly have opposite opening and closing operations and are interlocked to form a second signal switching circuit 30.

The output of the first high frequency amplifier circuit 18 is mixed with a local oscillation signal oscillated from a first local oscillation PLL frequency synthesizer 34 in a first mixing circuit 32.
The mixed output is given to the first intermediate frequency amplification circuit 36. Only the intermediate frequency signal is amplified and extracted by the first intermediate frequency amplification circuit 36 and given to the first demodulation circuit 38, where it is demodulated into an audio signal. This audio signal is the first
The sound is amplified by the audio amplification circuit 40 and amplified by the first speaker 42. Note that the system from the first high frequency amplification circuit 18 to the first speaker 42 supports the 144 MHz band and the 43 MHz band.
A first receiving system is formed that can receive any signal in the 0 MHz band.

[0005] Similarly, the second high frequency amplification circuit 2
The output of 2 is sent to the second local oscillation PLL in the second mixing circuit 44.
It is mixed with the local oscillation signal oscillated from the frequency synthesizer 46, and the mixed output is given to the second intermediate frequency amplification circuit 48. Only the intermediate frequency signal is amplified and extracted by the second intermediate frequency amplification circuit 48 and provided to the second demodulation circuit 50, where it is demodulated into an audio signal. This audio signal is amplified by the second audio amplification circuit 52 and amplified from the second speaker 54. Note that the system from the second high-frequency amplification circuit 22 to the second speaker 54 forms a second receiving system that can receive signals in either the 144 MHz band or the 430 MHz band.

In this configuration, when the first receiving system receives one signal in the 144 MHz band and the second receiving system receives one signal in the 430 MHz band, the state shown in FIG. 4 is set. That is, switching data for closing the first switch 16 and opening the second switch 20 is given to the first signal switching circuit 28 from a central processing unit (not shown). Further, a third switch 2 is connected to the second signal switching circuit 30.
Switching data is provided that causes the fourth switch 26 to close and the fourth switch 26 to open. At the same time, the central processing unit gives the first local oscillation PLL frequency synthesizer 34 N data for receiving a predetermined signal in the 144 MHz band, and the second local oscillation frequency synthesizer 46 receives a predetermined signal in the 430 MHz band. N data are given to do this. Then, the 144 MHz band signal that has passed through the first filter 12 is applied to the first high frequency amplifier circuit 18 via the first switch 16, and the 430 MHz band signal that has passed through the second filter 14 is applied via the third switch 24. The signal is applied to the second high frequency amplification circuit 22. Here, the frequencies of the intermediate frequency signals of the first and second receiving systems are different to prevent spurious signals, and the local oscillation signals oscillated from the first and second local oscillation PLL frequency synthesizers 34 and 46 are Set each so that they are not included in the other's frequency band.

[0007] When two signals having different frequencies within the 430 MHz band are simultaneously received by the first and second receiving systems, the central processing unit sends the first signal to the first signal switching circuit 28, although not shown. Switching data that causes the switch 16 to open and the second switch 20 to close is provided, and switching data that causes the second signal switching circuit 30 to close the third switch 24 and open the fourth switch 26 is provided. At the same time, appropriate N data is provided from the central processing unit to the first and second local oscillation PLL frequency synthesizers 34 and 46, respectively. Then, 430M that passed through the second filter 14
After the Hz band signal passes through the third switch 24, it is branched into two, one of which is sent to the first through the second switch 20.
One signal is applied to the high frequency amplification circuit 18, and the other is applied to the second high frequency amplification circuit 22.

Although not shown, when two signals with different frequencies within the 144 MHz band are simultaneously received by the first and second receiving systems, the central processing unit sends the first signal to the first signal switching circuit 28. Switching data that causes the switch 16 to close and the second switch 20 to open is provided, and the second signal switching circuit 30 causes the third switch 24 to open and the fourth switch 2 to open.
Switching data is provided to close 6. At the same time, appropriate N data is provided from the central processing unit to the first and second local oscillation PLL frequency synthesizers 34 and 46, respectively. Then, 144MH that passed through the first filter 12
After the Z-band signal passes through the first switch 16, it is branched into two, one of which is applied to the first high-frequency amplification circuit 18, and the other is applied to the second high-frequency amplification circuit 22 via the fourth switch 26. It will be done.

[0009]

[Problems to be Solved by the Invention] In the conventional radio receiver shown in FIG. There is a problem in that reception sensitivity is lowered compared to when signals in different frequency bands are received in each system. This means that when the first and second receiving systems receive signals in different frequency bands, the signals received by one antenna 10 are separated by frequency band by the first and second filters 12 and 14. While each signal is given to one receiving system, the first and second receiving systems receive two signals within the same frequency band.
When receiving two signals at the same time, one signal separated by frequency band is further divided into two and given to the first and second receiving systems, so the energy of the signal given to each receiving system is reduced. This is because it becomes about half.

The present invention has been made in view of the circumstances of the conventional radio receiver, and is a radio receiver that is capable of simultaneously receiving two signals within the same frequency band without causing a decrease in receiving sensitivity. The purpose is to provide a receiver.

[0011]

[Means for Solving the Problems] In order to achieve the above object, the radio receiver of the present invention provides a radio receiver that supplies a signal received by one antenna to a plurality of reception systems.
A signal switching circuit is interposed between the antenna and a high frequency amplification circuit of at least one receiving system, and a central processing unit controls the local oscillation signals of the plurality of receiving systems and simultaneously controls the signal switching circuit, When receiving signals within the same frequency band using one receiving system, the signal switching circuit is switched to a through circuit so that the signal received by the antenna is given to the one receiving system, and the signals within the same frequency band are When receiving signals using a plurality of receiving systems, the signal switching circuit is configured to switch the signal in the same frequency band received by the antenna to the plurality of receiving systems via an amplifier circuit and a distribution circuit. ing.

0012

[Operation] When multiple signals in the same frequency band are received simultaneously by multiple receiving systems, the signal in the frequency band to be received is amplified by an amplifier circuit, and the amplified output is distributed to the multiple receiving systems by a distribution circuit. Therefore, by appropriately setting the gain of the amplifier circuit, a signal can be given to the receiving system with energy equivalent to the energy of the signal received by the antenna. When a signal in one frequency band is received by one receiving system, the signal switching circuit is a through circuit, so that no deterioration occurs in the receiving characteristics. Moreover, since the signal switching circuit is controlled by the central processing unit in conjunction with the setting of the received signal by the receiving system, the operation does not become complicated.

[0013]

[Example] The following is an example of the present invention shown in FIGS. 1 and 2.
Explain with reference to. FIG. 1 is a block circuit diagram showing a state in which two signals of different frequencies in the 430 MHz band are simultaneously received by two receiving systems in an embodiment of the wireless receiver of the present invention, and FIG. 2 is a block circuit diagram showing the wireless receiver of FIG. 144MHz at receiver
FIG. 2 is a block circuit diagram showing a state in which one signal in each of the 430 MHz and 430 MHz bands is simultaneously received by each receiving system. 1 and 2, circuit blocks that are the same as those in FIG. 4 are given the same reference numerals and redundant explanations will be omitted.

In FIG. 1, the signal that has passed through the first filter 12 is applied to a common terminal c of a first switch 60. One selection terminal a of this first switch 60 is connected to a first amplifier circuit 62, and its amplified output is sent to a first distribution circuit 64.
given to. One of the signals branched into two by the first distribution circuit is applied to one selection terminal a of the second switch 66, and the other is applied to the second high frequency amplification circuit 22. Further, the other selection terminals b and b of the first and second switches 60 and 66 are connected to each other, and the common terminal c of the second switch 66 is connected to the first high frequency amplification circuit 18. 1st and 2nd
A first signal switching circuit 68 is formed by the switches 60 and 66, and the first and second signals are switched according to switching data from the central processing unit.
The switches 60 and 66 are placed in a state where the common terminals c and c are both connected to one selection terminal a and a, a state where the common terminals c and c are both connected to the other selection terminal b and b, and a state where the common terminal c is connected to the other selection terminal b and b. , c are not connected to any selection terminal.

Furthermore, the signal that has passed through the second filter 14 is applied to the common terminal c of the third switch 70. One selection terminal a of this third switch 70 is connected to the second amplifier circuit 72.
and its amplified output is given to the second distribution circuit 74. One of the signals branched into two by the second distribution circuit is applied to one selection terminal a of the fourth switch 76, and the other is applied to the first high frequency amplification circuit 18. And also, the other selection terminal b of the third and fourth switches 70 and 76,
b are connected to each other, and a common terminal c of the fourth switch 76 is connected to the second high frequency amplification circuit 22. A second signal switching circuit 78 is formed by the third and fourth switches 70 and 76, and depending on switching data from the central processing unit, the third and fourth switches 70 and 76 are connected to one of the common terminals c and c. A state in which the selection terminals a, are connected to a, a state in which the common terminals c, c are both connected to the other selection terminal b, b, and a state in which the common terminal c is connected to the other selection terminal b, b.
, c are not connected to any selection terminal.

In this configuration, when two signals of different frequencies within the 430 MHz band are simultaneously received by the first and second receiving systems, the first and second signal switching circuits 68 are switched by switching data from the central processing unit. , 78 are each set to the state shown in FIG. That is, the first and second switches 60 and 66 are set in a state where the common terminals c and c are not connected to any selection terminal, and the third and fourth switches
The switches 70 and 76 are put in a state where the common terminals c and c are both connected to one selection terminal a and a. Then, the output signal of the second filter 14 is applied to the second amplifier circuit 72 via the third switch 70 and is amplified. The amplified output is branched into two by the second distribution circuit 74, one of which is applied to the first high frequency amplification circuit 18, and the other is applied to the second high frequency amplification circuit 22 via the fourth switch 76. Here, by appropriately setting the gain of the second amplifier circuit 72, the energy of the signal given to the first and second high frequency amplifier circuits 18 and 22 can be made equal to or greater than the output signal of the second filter 14. It can be an energy signal. Therefore, two signals with different frequencies within the 430 MHz band can be simultaneously received by the first and second receiving systems without reducing reception sensitivity.

[0017] Also, in the first receiving system, 1 of the 144 MHz band
One signal in the 430MHz band is received in the second receiving system.
When receiving two signals, the first and second signal switching circuits 68 and 78 are respectively set to the state shown in FIG. 2 by switching data from the central processing unit. That is, the first, second, third, and fourth switches 60, 66, 70, and 76 are connected to the common terminals c, c, c, and the other selection terminals b and b.
, b, and b. Then, the first and second
The signal switching circuits 68 and 78 are both formed as through circuits, and the output of the first filter 12 is given as is to the first high frequency amplification circuit 18, and the output of the second filter 14 is given as is to the second high frequency amplification circuit 22. . therefore,
There is no deterioration in the reception characteristics of the radio receiver.

Note that when two signals in the 144 MHz band are simultaneously received by the first and second receiving systems, the first and second switches 60 and 66 are connected to the common terminal c, although not shown.
The third and fourth switches 70 and 76 may be set so that the common terminals c and c are not connected to any of the selection terminals, while the third and fourth switches 70 and 76 are connected to one of the selection terminals a and a, respectively.

FIG. 3 is a block circuit diagram of another embodiment of the wireless receiver of the present invention. In FIG. 3, circuit blocks that are the same or equivalent to those in FIGS. 1 and 2 are given the same reference numerals and redundant explanations will be omitted.

In the embodiment shown in FIG. 3, the first amplifier circuit 62 and the first distribution circuit 64 of the embodiment shown in FIG.
A switch circuit 80 is interposed between the filter 12 and the first high-frequency amplification circuit 18, instead of the first signal switching circuit 68, and is opened or closed according to switching data from the central processing unit. Further, the second signal switching circuit 78 controls the third and fourth switches 7 according to switching data from the central processing unit.
0 and 76 are both common terminals c and c are one selection terminal a,
It can be set to two states: a state in which it is connected to the terminal a, and a state in which the common terminals c and c are both connected to the other selection terminals b and b.

In such a configuration, as shown in FIG. 3, the switch circuit 80 is
is opened, and the third and fourth switches 70 and 76 of the second signal switching circuit 78 connect the common terminals c and c to one of the selection terminals a and a, so that the antenna 10 receives signals. The signal which has passed through the second filter 14 is amplified and divided into two parts, which are applied to the first and second high frequency amplification circuits 18 and 22. Therefore, similarly to the embodiment shown in FIG.
Two signals can be received simultaneously by two receiving systems.

Although not shown, the switch circuit 80 is closed by switching data from the central processing unit, and the third and fourth switches 70 and 76 of the second signal switching circuit 78 are connected to the common terminal c, By connecting both terminals b and b to the other selection terminals b and b, the first filter 1
The signal that has passed through the filter 2 is applied as is to the first high frequency amplification circuit 18, and the signal that has passed through the second filter 14 is applied as it is to the second high frequency amplification circuit 22. Therefore, similarly to the embodiment shown in FIG.
It is possible to receive one signal at a time in each Hz band.

[0023] In the above embodiment, the first and second
Although the signal switching circuits 68, 78 and the switch circuit 80 are shown using mechanical switches, the present invention is not limited to this, and it goes without saying that they may be constructed using semiconductor switches such as diodes. In addition, the receiving frequency band is
The combination is not limited to the 144 MHz band and 430 MHz band, but may be any combination of the same or different appropriate frequency bands. Furthermore, three or more receiving systems may be provided so that three or more signals within the same frequency band can be received simultaneously. Then, the audio signals respectively output from the first demodulation circuit 38 of the first receiving system and the second demodulating circuit 50 of the second receiving system are fed to one common audio amplification circuit, so that the plurality of receiving systems It may be configured such that one audio amplification circuit and speaker are shared by the two.

[0024]

Since the radio receiver of the present invention is constructed as described above, it provides the following special effects.

[0025] A plurality of signals within the same frequency band can be received simultaneously without reducing reception sensitivity. Further, when receiving signals in different frequency bands, the reception characteristics of the radio receiver are not deteriorated in any way. Further, since the signal switching circuit is switched and controlled in conjunction with the setting of the received signal, the operation is not complicated and the operation is excellent.

[Brief explanation of drawings]

FIG. 1 shows an embodiment of the wireless receiver of the present invention.
FIG. 2 is a block circuit diagram showing a state in which two signals having different frequencies in the 0 MHz band are simultaneously received by two reception systems.

FIG. 2 is a block circuit diagram showing a state in which the radio receiver of FIG. 1 simultaneously receives one signal in each of the 144 MHz band and 430 MHz band in each receiving system.

FIG. 3 is a block circuit diagram of another embodiment of the wireless receiver of the present invention.

FIG. 4 is a block circuit diagram showing an example of a conventional wireless receiver.

[Explanation of symbols]

10 Antenna 18 First high frequency amplification circuit 22 Second high frequency amplification circuit 34 First local oscillation PLL frequency synthesizer 46
PLL frequency synthesizer 60 for second local oscillation
First switch 62 First amplifier circuit 64 First distribution circuit 66 Second switch 68 First signal switching circuit 70 Third switch 72 Second amplifier circuit 74 Second distribution circuit 76 Fourth switch 78 Second signal switching circuit

Claims (1)

[Claims] Claim 1. A radio receiver that supplies a signal received by one antenna to a plurality of receiving systems, wherein a signal switching circuit is interposed between the antenna and a high frequency amplification circuit of at least one receiving system, The arithmetic unit controls the local oscillation signals of the plurality of reception systems and at the same time controls the signal switching circuit, so that when signals within the same frequency band are received by one reception system, the signals received by the antenna are The signal switching circuit is switched to a through circuit so as to feed the signal to one receiving system, and when signals within the same frequency band are received by multiple receiving systems, the signal within the same frequency band received by the antenna is switched to an amplifying circuit. A wireless receiver characterized in that the signal switching circuit is switched so as to provide the signal to the plurality of receiving systems via a distribution circuit and a distribution circuit.