JPH0693792B2 - Radio control receiver - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an improvement of a radio control receiver in a radio transmission / reception system.

[Conventional technology]

When remotely controlling a model airplane or helicopter by a radio control method, weak radio waves in a predetermined frequency band that does not require a license are used. Since radio waves in such a frequency band are used not only for radio control but also for other purposes, they may be used in close proximity. Therefore, it is not sufficiently protected from interference such as jamming radio waves, and it is difficult to secure a stable communication system. Therefore, in recent years, as a signal system for radio control transceivers, a signal system based on a digital system such as PCM has been used instead of an analog modulation system.

In such a signal system, in the analog modulation system, if the reception state deteriorates, the control state also gradually deteriorates, so that it is possible to detect an abnormality before the control is completely disabled. . However, in the case of the digital modulation method using a pulse code, control may be suddenly disabled due to a decrease in electric field strength, interference, or the like. FIG. 4 is a circuit diagram showing an example of a conventional PCM receiver. In this figure, the input from the antenna 1 is passed through the high frequency amplification circuit 2 and the frequency conversion circuit 3
And converted to an intermediate frequency signal. Then, through the intermediate frequency amplification circuit 4, the detection / waveform shaping circuit 5
The PCM signal is taken out and the data decoding circuit 6 takes out a parallel control signal. This signal controls a plurality of servos such as an airplane. A redundant bit such as CRC is added to the PCM signal sent from the transmitter to detect an error. If an error is detected, the data code circuit 6 outputs an error detection signal. In this case, the rotation angle of each servo is held as it is every time an error signal is detected. In this way, there is a time lag in the operation of the transmitter, but if the normal transmission state is restored, the operation can be continued.

[Problems to be Solved by the Invention]

However, when a strong nozzle is added or interference radio waves are continuously given, the hold state continues. In this case, the control becomes impossible, and there is a drawback that the vehicle may crash when remotely controlling a flying object such as an airplane.

The inventions of claims 1 and 2 of the present application have been made in view of the problems of such a conventional radio control receiver, and prevent a crash even if an interfering radio wave or noise is superposed. This is a technical issue.

[Means for Solving the Problems]

The invention of claim 1 of the present application is a radio control receiving device for receiving the same pulse-code-modulated radio waves at different carrier frequencies, and receives and demodulates PCM signals at respective carrier frequencies. A plurality of receiving sections for decoding the control signals and outputting the control signals and the error signals, and a switching processing section for receiving the control signals and the error signals of the plurality of receiving sections and selecting the control signals which are not in the error state. It is what

Further, the invention of claim 2 of the present application is a radio control receiving device having a radio wave which is pulse code modulated at a specific carrier frequency, and is connected to a plurality of antennas installed at different positions and a plurality of antennas respectively. A plurality of receiving units that receive and demodulate PCM signals of a specific carrier frequency and decode the PCM signals to output control signals and error signals, and control signals and error signals of the plurality of receiving units are provided. , And a switching processing unit that selects a control signal that is not in an error state.

[Action]

According to the invention of claim 1 of the present application having such a feature, the pulse code-modulated signals obtained from the antennas are given to the plurality of receiving units, respectively. In this case, since the frequencies of the receiving units are different from each other, even if noise or the like is superimposed on one of the radio waves, a normal signal is output from the other receiving unit. Therefore, a normal control signal can be obtained by switching the control signal by the switching processing unit based on the error signal obtained from each receiving unit.

Further, according to the invention of claim 2 of the present application, by providing the antennas at different positions, even if one of the receiving sections becomes an error and an error signal is output, a normal control signal is output from the other receiving section. Therefore, the switching processing section selects a normal control signal.

〔Example〕

FIG. 1 is a block diagram showing the configuration of a receiving apparatus according to an embodiment which embodies the invention of claim 1 of the present application. In the figure, the anthena 11 is connected to the first and second receivers 12 and 13. Transmitters not shown here have different frequencies, for example
The frequencies of 27MHz and 4MHz are used as carriers, and the signals of the same PCM code with CRC error correction code are transmitted respectively. The first and second receivers receive signals with different carrier frequencies. It is a receiver. The first receiving section 12 has an antenna coupling circuit 14 tuned to the first frequency, and its output is given to the frequency conversion circuit 16 via the high frequency amplification circuit 15. The output of the frequency conversion circuit 16 is given to the intermediate frequency amplification circuit 17, amplified as an intermediate frequency, and then given to the detection and waveform shaping circuit 18. The output of the waveform shaping is given to the data decoding circuit 19, respectively. The blocks 21 to 26 of the second receiving unit 13 are the same as the blocks 14 to 19 of the first receiving unit 12 except that the frequencies to be received are different, and the description thereof will be omitted.

Now, the data decoding circuits 19, 26 of the first and second receivers 12, 13
The parallel control signal and the error signal thus obtained are given to the switching processing unit 27, respectively. The switching processing unit 27 switches to a normal control signal based on the error signals of the data decoding circuits 19 and 26, and its output is given to the plurality of servo circuits 28a, 28b ... As a demodulated control signal.

Next, the configuration of the switching processing unit 27 will be described with reference to FIG. The switching processing unit 27 is a switching circuit such as an analog switch to which the parallel outputs of the first and second receiving units 12 and 13 are respectively applied.
It has 31 and is adapted to be switched by an error signal. The error signal of the data decoding circuit 19 of the first receiving unit 12 is given to the inverter 32 as shown, and the error signal of the second receiving unit 13 is connected in cascade to the inverters 33, 3.
Given to 4. The outputs of these inverters are resistors R1 and R2.
Are commonly connected to each other, and the common contact is provided to the inverting input terminal of the comparator 35. The non-inverting input terminal of the comparator 35 has a variable resistor for switching between the first and second receiving sections.
The middle point of VR is connected, and when an error signal is obtained from any of the circuits, the analog switch 31 is switched to obtain the parallel control signal of the receiving unit in which no error has occurred. When both receivers 12 and 13 are operating normally, the same signal is obtained from both receivers, so the analog switch preferentially selects either one.

As described above, in the present invention, by using the signals of a plurality of carrier frequencies, even when the signal of one of the frequencies is added with noise or an interfering radio wave and normal reception cannot be performed,
The control signal is switched so as to be a control signal for the data decoding circuit that can be normally received based on the error signal. Then, there is no servo hold, and a normal reception state can always be obtained.

Next, an embodiment embodying the invention of claim 2 of the present application will be described with reference to FIG. In this embodiment, the signal from the transmitter that is pulse code modulated in a specific frequency band is
The first and second receivers 12 and 13 are adapted to receive the signals. In this embodiment, independent antennas 41 and 42 are provided at positions apart from the body of an airplane or the like. The outputs of these antennas 41, 42 are given to the first and second receivers 12, 13. The configurations of the first and second receivers 12 and 13 are the same as those in the above-described embodiment, and the high frequency amplification circuits 43 and 44, the frequency conversion circuits 45 and 46, the intermediate frequency amplification circuits 47 and 48, the detection and waveform shaping. Circuits 49, 50 are provided. The outputs of the data tecode circuits 51 and 52 are given to the switching processing unit 27. The configuration of the switching processing unit 27 is similar to that of the first embodiment described above.

In this embodiment, antennas are provided at different positions on the airplane, so that diversity reception is possible.
Therefore, even if noise is superimposed, a normal signal can be obtained through the switching processing unit 27 when a normal signal is demodulated by either one of the receiving systems. Therefore, the servo hold state disappears, and the possibility of an airplane crashing can be greatly reduced.

Further, although two receiving units are provided in each of the first and second embodiments of the present application, it goes without saying that a larger number of receiving units may be provided. It is also possible to install the antennas of the first embodiment independently and combine them with diversity reception.

〔The invention's effect〕

Therefore, according to the inventions of claims 1 and 2 of the present application, even if an error signal is obtained from one of the receiving units due to superimposition of an interfering radio wave or noise, a normal signal is output from the other receiving unit. An effect that a correct code signal can be demodulated is obtained.

[Brief description of drawings]

FIG. 1 is a block diagram showing an overall configuration of an embodiment embodying the invention of claim 1 of the present application, FIG. 2 is a circuit diagram showing a detailed configuration of a switching processing unit, and FIG. 2 is a block diagram showing an embodiment of the invention of FIG. 2, and FIG. 4 is a block diagram showing an example of a conventional receiver. 1,11,41,42 …… Acatena, 12 …… First receiver, 13 ……
Second receiving section, 6,19,26,51,52 ... Data decoding circuit, 27 ... Switching processing section, 28a, 28b ... Servo

Claims (2)

[Claims] 1. A radio control receiver for receiving the same pulse code modulated (hereinafter referred to as "PCM") radio waves at different carrier frequencies, each of which receives and demodulates a PCM signal at each carrier frequency. A plurality of receiving units that decode the PCM signal and output control signals and error signals; and a switching processing unit that receives the control signals and error signals of the plurality of receiving units and selects a control signal that is not in an error state. A radio control receiver characterized by the above. 2. A radio control receiving device having a radio wave that is pulse code modulated at a specific carrier frequency, wherein a plurality of antennas are installed at different positions, and a plurality of specific antennas are respectively connected to the plurality of antennas. A plurality of receiving units that receive and demodulate the PCM signals of the carrier frequency and decode the PCM signals to output control signals and error signals, and control signals and error signals of the plurality of receiving units are given and And a switching processing section for selecting a non-control signal.