JPH0746782B2 - Receiving machine - Google Patents

Description

The present invention relates to a receiver used in, for example, an FM wireless microphone system.

[Background technology and its problems]

For example, in the United States, VHF television channels 7 to 13 channels (174 MHz to 216 MHz) are allowed as empty frequency bands for wireless microphone systems. Each TV channel from channel 7 to channel 13 is further divided into channels for wireless microphone systems every 200 KHz, and channels for wireless microphones of 24 waves are allocated within a channel of one television channel. Therefore, a total of 168 waves of channels for wireless microphones are allocated between the 7th and 13th channels of TV Jiyoung.

In the conventional wireless microphone system, a crystal oscillator circuit was used. The oscillation frequency of a crystal oscillator circuit is determined by the natural frequency of the crystal. Therefore, the conventional wireless microphone system can be used only in the channels of the wireless microphones assigned as described above, which have a specific frequency determined by the frequency of the crystal built into the system. Therefore, when the channel to be used is disturbed by external noise, or when multiple microphones are used at the same time, the built-in crystal should be changed when it is necessary to change the channel to avoid interference. I needed to replace it. Replacing the crystal in this way is very time-consuming, and the crystal is very expensive.

Therefore, it is conceivable to construct a wireless microphone system that can cover a large number of channels, for example, using an oscillation circuit based on a PLL. Thus, if many channels can be used in one wireless microphone system, a plurality of microphones can be used at the same time. However, even if a large number of channels are covered in this way, a channel that is affected by, for example, third-order intermodulation is substantially unusable.
Among the 24 channels of the wireless microphones assigned to one channel of the television, it is a combination of 6 channels, for example, that can be used at the same time without mutual interference. Since special conditions are added to this combination, it is difficult to select which combination is appropriate. If this selection is not done properly, it is not possible to use multiple microphones at the same time, even in a wireless microphone system that can cover a large number of channels, due to mutual interference.

[Object of the Invention]

Therefore, an object of the present invention is to provide a receiver capable of selecting a large number of channels, which can easily perform an appropriate channel setting which does not cause mutual interference when using a plurality of wireless microphones at the same time. To provide.

[Outline of Invention]

The present invention is a receiver that divides one band into a predetermined number of channels and selectively receives the divided channels, and a combination of a plurality of channels that do not cause mutual interference in the divided channels. This is a receiver that can be selected and can receive any of the selected multiple channels.

〔Example〕

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

FIG. 1 shows a front panel and a rear panel of this embodiment. In FIG. 1, reference numeral 1 denotes a case of the device body. As shown in FIG. 1A, the front panel includes a power switch 2, a monitor jack 3 and a monitor control knob 4, a channel select button 5, a television channel select button 6, a group select button 7, and these channels and groups. A set button 8 used for setting is provided. Channel Select Button 5, TV Jiyoung Channel Select Button 6,
In order to prevent erroneous operation, the group select button 7 is designed so that the channel or group cannot be set even while the set button 8 is being pressed, even if the respective buttons are pressed. The set channels and groups are displayed on the liquid crystal display 9.

The monitor jack 3 is a jack for connecting, for example, a headphone for monitoring. The volume of this monitor is set by the control knob 3. On the rear panel, as shown in FIG. 1B, audio output terminal 10 and antenna terminal 1
1, an external power supply terminal 12 is provided.

What is the group set by the group select button 7?
This is a combination of channels that do not interfere with each other when using multiple microphones at the same time. As shown in FIG. 2, six groups of the groups 1 to 6 are set from 7 to 13 of the television group, as shown in FIG. Of the groups set in each television channel, groups 2 to 4 are groups in which wireless microphone channels that do not interfere with each other are combined in the same television channel. Groups 5 and 6
It is a group that combines wireless microphone channels that do not interfere with each other not only within each same television channel but also between other channels.
Group 1 is provided so that all the set channels can be used.

The channels and groups of this wireless microphone system are set and used as follows.

If the number of microphones used at the same time is 6 or less, first set one of the empty channels of the television using the television channel select button 6 and then set the group to group 2 using the group select button 7. Set. As an example, if the 7 channels of the TV series are empty channels, and the 7 channels of the TV series are set and then set to group 2, as shown in FIG. 13 Channel and 22
Six channels, 24 and 24, can be set. These six channels do not interfere with each other. Therefore, the user sets each wireless microphone to the same group,
By setting the channels of the wireless microphones that can be set within this group, a total of 6 microphones can be used at the same time without mutual interference.

When it is set in the group 2 and used, for example, when it is disturbed by an external beat or noise, the group is reset to the group 3 or the group 4. Groups 3 and 4
However, as mentioned above, the channels are set so that they do not interfere with each other. Therefore, by setting to group 3 or 4, it is possible to avoid these beats and noises, and a plurality of microphones can be used simultaneously as in the case of setting to group 2.

Even if it is set to group 3 or 4, if it is still disturbed by beats or noise, it can be avoided by resetting it to the empty channel of another television and performing the same operation. .

If the number of microphones used at the same time is 7 or more,
Set the group as follows. First, the empty channels of TV Jiyoung are, for example, 7 channels, 9 channels, 11 channels.
In odd-numbered areas such as 13 and 13, set the group to group 5. The TV channel's sky channel is 8 channels, 10 channels, 12
If the channel is an even number such as a channel, set it to group 6. Groups 5 and 6 are groups in which channels do not interfere with each other not only within the same television channel but also between other channels.

When set to group 5, as shown in Fig. 2, the 7-channel of TV-Jeon is a wireless microphone. Microphone channel 1
Channel, 9 channels, 23 channels, 11 channels of TV channel, 14 channels of wireless microphone channels, 14 channels of 19 channels, 13 channels of television channels, 3 channels of wireless microphones and 23 channels, and 13 channels in total can be set. It will be possible. These 13 channels are a combination of channels that do not interfere with each other. Therefore, up to 13 microphones can be used simultaneously.

When set to group 6, as shown in Fig. 2, the TV microphone's 8 channels are wireless microphone channels 1 channel, 7 channels, 11 channels, 13 channels, 22 channels, 24 channels, and 10 channels of TV channels. You can set 1 channel, 9 channels, 23 channels of wireless microphone channel, and 14 channels, 19 channels of wireless microphone channel with 12 channels of TV Gyon, and a total of 11 channels can be set. These 11 channels are a combination of channels that do not interfere with each other. Therefore, up to 11 microphones can be used at the same time.

A desired channel in the group set as described above is set by the channel select button 5.

FIG. 3 shows the configuration of an embodiment of the present invention. In FIG. 3, reference numeral 15 is a reception channel setting section. The reception channel setting unit 15 is composed of a CPU 16, a ROM 17, a PLL 18, an operation key 19, and a liquid crystal display 20. Channel data of each group is written in ROM17. CP
U16 is supplied with key operation signals from operation keys 19 such as channel select button 5, television channel select button 6, set button 8 and the like, and the CPU 16 determines the frequency division ratio of PLL 18 based on this key operation signal and ROM 17 data. The output of the CPU 16 controls the oscillation frequency of the VCO of the PLL 18. The groups and channels determined by the CPU 16 are displayed on the liquid crystal display 20.

FIG. 4 shows a flow chart of the operation of the reception channel setting unit 15. First, it is determined whether or not the set button 8 has been pressed and the set switch has been turned on. (Step). When the set switch is off,
It will be interrupted (step). When the set switch is turned on, the group select button 7 is pressed to determine whether the group selector is turned on (step). When the group selector is turned on, the group data is changed (step).
When the group selector is off, it is judged whether or not the television selector button 6 and the channel select button 5 are pressed to turn on the channel selector (step). When the channel selector is turned on, the channel data is changed (step). If the channel selector is off, return to step.

The address of the channel data is determined from the group obtained in step and the channel obtained in step (step). The determined address is ROM17
And the channel data is read from the ROM 17 (step). PLL18 from the data read from ROM17
The division ratio of is calculated by the CPU 16 (step). The PLL 18 is set to the division ratio calculated by the CPU 16 (step). Display the channel and group on the LCD display 20 (step). When the channel and group are displayed on the LCD display 20, the process returns to step.

The output of the PLL 18 whose frequency is controlled in this way is supplied to the first frequency conversion circuit 21, as shown in FIG. The first frequency conversion circuit 21 is supplied with the FM-modulated high frequency signal from the wireless microphone from the antenna terminal 22 through the high frequency amplification circuit 23. With the first frequency conversion circuit 21
The high frequency signal is converted to the first intermediate frequency of 49.4 MHz by the output of the PLL 18, for example.

The output of the first frequency conversion circuit 21 is a first intermediate frequency amplification circuit.
It is amplified via 24 and supplied to the second frequency conversion circuit 25. The output of the second local oscillation circuit 26 is supplied to the second frequency conversion circuit 25. The second local oscillation circuit 26 is a fixed frequency oscillation circuit using, for example, a crystal oscillation circuit. In the second frequency conversion circuit 25, from the first intermediate frequency, for example
Converted to the second intermediate frequency of z.

The output of the second frequency conversion circuit 25 is the second intermediate frequency amplification circuit.
It is amplified via 27 and supplied to the FM detection circuit 28. The FM detection circuit 28 is, for example, a ratio detection detection circuit. The output of the FM detection circuit 28 is supplied to the low frequency amplification circuit 30 via the muting circuit 29. The output of the low-frequency amplifier circuit 30 is supplied to the output terminal 31, and the audio output is taken out from the output terminal 31.

The combination of channels in each group may be another combination as long as it does not cause mutual interference.

[Application example]

The invention can likewise be used as a receiver for AM-modulated wireless microphone systems.

[Effects of the Invention] According to the present invention, since the PLL is used in the oscillation circuit, it is possible to realize a wireless microphone system capable of receiving a large number of channels and using a plurality of channels. Further, according to the present invention, since the combination of frequencies that do not interfere with each other is set in advance as a group, the channel of the wireless microphone is set as the same group as the set group, and is set in this group. If you select a possible channel, you can use multiple microphones at the same time without interfering with each other.

[Brief description of drawings]

FIG. 1 is a front view and a rear view of an embodiment of the present invention, and FIG.
FIG. 3 is a schematic diagram used to explain one embodiment of the present invention, FIG. 3 is a block diagram of one embodiment of the present invention, and FIG. 4 is a flow chart used to explain one embodiment of the present invention. 5: Channel select button, 6: Television channel select button, 7: Group select button, 8: Set button, 15: Receive channel setting section, 16: CPU, 17: ROM, 18: PL
L.

Claims (1)

[Claims] 1. A reception channel setting means for selecting and receiving a signal of a frequency corresponding to a reception channel, a channel control means for controlling the reception channel setting means, and the channel control means are third harmonics. A combination of a plurality of reception channels that does not interfere with waves is stored as a reception channel group, and a channel group input unit for designating the channel group is provided, and the channel group is input by the channel group input unit. A receiver characterized in that, when specified, the receiving channel is controlled to be set from the receiving channels included in the specified channel group.