JPS6036912Y2 - wireless microphone - Google Patents

Description

[Detailed description of the invention] This invention relates to a wireless microphone having an external modulation function and equipped with a jack for connecting an external microphone. The purpose is to provide

Generally, a wireless microphone with an external modulation function is equipped with a six-bin jack 5 as shown in Fig. 1, and when the wireless microphone itself is used, a plug with an external microphone connected to the jack 5 is not inserted. A low frequency signal from a microphone unit section 1 including an electret condenser microphone unit is supplied to a high frequency oscillation section 2 through an audio signal transmission line 6, and is frequency modulated (FM) with an oscillation frequency signal of 76 to 90 MHz. The FM signal from 2 passes through a transmission line 7, is amplified by a high frequency amplification section 3, and is sent to an antenna 4.
It is radiated as FM radio waves.

On the other hand, when adding an external modulation function by inserting a plug (not shown) into the 6-pin jack 5, set terminal a to the ground side and terminal C to the hot side so that the low frequency signal from the external microphone passes through the resistor R1. The signal enters the transmission line 6 via the signal line and is subjected to external modulation.

At this time, terminal a is connected to B power supply 8 of each part, and at the same time as the plug is inserted, movable terminal e separates from terminal d and terminal f
A capacitor C1 is connected between the terminals f and a to attenuate the FM signal supplied to the antenna 4 at the same time as the plug is inserted.

However, the wireless microphone configured as described above requires a capacitor C1 for the purpose of attenuating the FM signal supplied to the antenna 4 in order to add an external modulation function. This requires a large 6-pin jack 5, which poses a problem in that it is difficult to miniaturize the wireless microphone itself.

The present invention is intended to eliminate such conventional drawbacks, and the present invention will be described below with reference to drawings of embodiments.

FIG. 2 shows an embodiment of the wireless microphone of the present invention. In the figure, 11 is a microphone unit section including an electret condenser microphone unit, and a low frequency signal from this microphone unit section 11 is transmitted through a transmission line 16 to a high frequency oscillator 12. , and is frequency modulated (FM) at an oscillation frequency of 76 to 90 MHz.

The FM signal from the oscillator 12 is applied to the high frequency amplification section 13 via the transmission line 17, where it is amplified and radiated from the antenna 14 as an FM radio wave.

Here, the high frequency amplification section 13 is configured as shown in FIG. 3, and the high frequency amplification section transistor TR1
Resistor B2 connected to the emitter resistor of 3-pin jack 1
The movable terminal 3 is inserted between the terminal C constituting the terminal C and the movable terminal 3 and is short-circuited.

On the other hand, when a plug connected to an external microphone is inserted into the 3-pin jack 15, a low frequency signal from the external microphone is applied to the terminal aa constituting the 3-pin jack 15, and the high-frequency oscillation is transmitted from the transmission line 16 through the resistor R1. The FM signal is applied to the high frequency amplification section 12 and similarly subjected to FM modulation, and the FM signal is amplified by the high frequency amplification section 13 and radiated from the antenna 14 as an FM radio wave.

At this time, the high-frequency amplifying section 13 connects the emitter of the high-frequency amplifying transistor TR□ to the resistor R.
Since power is supplied through the antenna 14, the supplied voltage is reduced by the voltage drop across the resistor R2, the amplification factor is reduced, and the FM radio waves radiated from the antenna 14 are attenuated.

As described above, according to the present invention, a 3-pin jack is used as the jack into which the plug to which the external microphone is connected is inserted, and when the plug is inserted into the 3-pin jack, a resistor is inserted to supply power to the high frequency amplification section. Since the wireless microphone is constructed in such a way that there is no need to use a large 6-pin jack as in the past, the wireless microphone itself can be made smaller.

[Brief explanation of drawings]

Figure 1 is a circuit diagram of a conventional wireless microphone.
FIG. 2 is a circuit connection diagram showing an embodiment of the wireless microphone of the present invention, and FIG. 3 is a specific circuit connection diagram of the main part thereof. 11...Microphone unit section, 12...
High frequency oscillation section, 13... High frequency amplification section, 14.
...Antenna, 15...Jack, R1
, R2...Resistance.

Claims (1)

[Scope of utility model registration request] FM modulates the low frequency signal from the built-in microphone unit,
A wireless microphone configured to amplify the FM signal in a high-frequency amplification section and radiate it as FM radio waves from an antenna. The normally closed switch is constructed by using a 3-pin jack equipped with a normally closed switch and a fixed terminal to which a low frequency signal from the external microphone is applied, and the fixed terminal is connected to the signal input terminal of the FM modulation means. A movable terminal is connected to the power supply end of the built-in microphone unit section and the FM modulation means, and a fixed terminal that is contacted by the movable terminal is connected to the power supply end of the high frequency amplification section, and each terminal of the normally closed switch. A wireless microphone characterized by a resistor inserted between the microphones.