KR200290284Y1 - Receiver of wireless microphone - Google Patents

Abstract

The present invention is provided with a reverse bias blocking diode that prevents RF bias of other channel receiving circuits from entering each channel receiving circuit, and accommodates each receiving circuit receiving dual channels in one printed circuit board without interference. The present invention relates to a wireless microphone receiver capable of reducing a production cost and a size of a receiver.

According to the present invention, in a wireless microphone receiver receiving an RF signal of a channel having a different frequency band and outputting it as an audio signal through a speaker, the receiving circuit of each channel is provided separately, wherein each receiving circuit is an antenna (ANTa) RF filters (T1a, T2a; T1b, T2b) for filtering RF signals input through; ANTb), low noise amplifiers (Q1a; Q1b) for low noise amplification of the filtered RF signal, and carrier frequencies in the amplified RF signal. Oscillators (X1a; X1b) for oscillating a reference frequency for removal, intermediate frequency mixers (T5a; T5b) for mixing carrier and oscillation frequencies to remove carrier frequencies, and intermediate frequency mixers (T5a; T5b). Intermediate frequency amplifiers Q3a and Q3b for amplifying the intermediate frequency, and detecting the AF signal at the intermediate frequency to keep the intensity of the AF signal constant and to cut off the signal having low sensitivity. Is connected to an automatic gain controller (U1a; U1b), an AF amplifier (U2a; U2b) for amplifying the AF signal output from the automatic gain controller (U1a; U1b), and the automatic gain controller (U1a; U1b). Mute (U3a, Q6a; U3b, Q6b) that suppresses input signals that do not have a signal-to-noise ratio in the AF signal, and compresses (U4a; U4b) that increase the signal-to-noise ratio by extending the compressed signal at the transmitter. The anode is connected to the ground of the oscillator (X1a; X1b) on the power input side of the automatic gain controller (U1a; U1b), and the cathode is connected to the power (VCC) input terminal of the automatic gain controller (U1a; U1b). The bias blocking diodes D10a and D10b are provided to prevent crosstalk between signals due to the intrusion of RF signal reverse bias of other channel receiving circuits, thereby preventing the occurrence of crosstalk between different channels on the same printed circuit board. To accommodate the receiving circuit Provided is a wireless microphone receiver characterized in that the present invention.

Description

Wireless microphone receiver {Receiver of wireless microphone}

The present invention relates to a wireless microphone receiver, and more particularly, to a wireless microphone receiver capable of reducing the production cost and the size of the receiver by receiving each receiving circuit for receiving a dual channel on a single printed circuit board without any confusion. will be.

In general, a wireless microphone uses RF (Radio Frequency) signals divided into a plurality of channels in the 200 MHz, 700 MHz, and 900 MHz bands defined by the information communication unit, and converts and transmits a voice signal to an RF signal during a transmission and reception period. The receiver of such a wireless microphone usually processes the frequency band of the wireless RF signal received through the antenna, amplifies the filtered RF signal, mixes the RF signal and the oscillation frequency, and filters and amplifies the mixed intermediate frequencies. Is repeated to remove the distortion or noise of the signal and send it to the audio output side to output the received RF signal as a voice signal. In this case, in order to prevent crosstalk between signals due to bias of the RF signal of each channel to the other channel, a receiver circuit corresponding to each channel is designed on a different printed circuit board (PCB), Each printed circuit board is accommodated inside the receiver case.

However, as the receiving circuits of each channel are designed on different printed circuit boards as described above, the number of printed circuit boards increases, the production cost increases, and the size of the receiver case increases as the stacked printed circuit boards are stacked. There is a problem. In addition, in order to stably operate MUTE, RSSI (Received Signal Strength Indicator) module which detects the strength of signal sensitivity or pop noise generated when the power is turned on by noise of AF (Audio Frequency) signal Due to IC (Integrated Circuit) for removing, there is a problem such as the size of the printed circuit board increases.

The present invention is to solve the above problems, an object of the present invention is to accommodate each receiving circuit for receiving a dual channel in a single printed circuit board without confusion to reduce the production cost and the size of the receiver wireless microphone It is to provide a receiver.

1 is a block diagram of a wireless microphone receiver according to the present invention

2 is a circuit diagram showing a first receiving circuit of the present invention

3 is a circuit diagram showing a second receiving circuit of the present invention;

4 is a circuit diagram showing an audio circuit of the present invention

5 is a circuit diagram showing a power supply unit of the present invention

Figure 6 is a perspective view of the state of use of the subject innovation

<Description of the symbols for the main parts of the drawings>

ANT. Antennas T1, T2. RF filter

Q1. Low Noise Amplifier X1. oscillator

T5. Medium Frequency Mixer Q3. Intermediate frequency amplifier

U1. Automatic gain controller U2. AF amplifier

U3, Q6. Mute U4. Squeezer

D10. Reverse bias blocking diode R31. Detection resistor

C53. Detection capacitor Q8. Switching transistor

SVR2. Variable resistor for signal delay

According to the present invention, in a wireless microphone receiver receiving an RF signal of a channel having a different frequency band and outputting it as an audio signal through a speaker, the receiving circuit of each channel is provided separately, wherein each receiving circuit is an antenna (ANTa) RF filters (T1a, T2a; T1b, T2b) for filtering the RF signal input through the; ANTb, Low Noise Amplifier (LNA) (Q1a; Q1b) for low noise amplification of the filtered RF signal, and amplification. An oscillator (X1a; X1b) oscillating a reference frequency to remove the carrier frequency from the received RF signal, an intermediate frequency mixer (T5a; T5b) for mixing the RF signal and the oscillation frequency to remove the carrier frequency, and the intermediate frequency mixer Intermediate frequency amplifiers Q3a and Q3b that amplify the intermediate frequencies generated by T5a and T5b, and detect the AF signal at the intermediate frequency to keep the AF signal constant and reduce sensitivity. An automatic gain controller (AGC) U1a; U1b for blocking and outputting a call; an AF amplifier U2a; U2b for amplifying the AF signal output from the automatic gain controller U1a; U1b; Mute (U3a, Q6a; U3b, Q6b) connected to the automatic gain controllers (U1a; U1b) to suppress noise by suppressing an input signal having no signal-to-noise ratio (SN ratio) in the AF signal, and compressed at the transmitting side. It includes a comparator (U4a; U4b) for extending the signal to increase the signal-to-noise ratio, and the anode is automatically connected to the ground of the oscillator (X1a; X1b) on the power input side of the automatic gain controller (U1a; U1b). The reverse bias blocking diodes D10a and D10b having a cathode connected to the power supply VCC input terminals of the gain controllers U1a and U1b are provided to block the intrusion of the RF signal reverse bias of another channel receiving circuit. The same printed circuit to prevent crosstalk The wireless microphone receiver, characterized in that the receiving circuit to accommodate the different channels in the plate are provided.

According to another feature of the present invention, a detection resistor (R31a; R31b) and a capacitor (C53a; C53b) connected to the other side of the automatic gain controller (U1a; U1b) connected to the ground side in parallel, The detection resistors R31a and R31b and the capacitors C53a and C53b are provided through the automatic gain controllers U1a and U1b so as to pass only when the intensity of the AF signal is greater than or equal to a predetermined value. .

According to still another feature of the present invention, a switching transistor Q8a; Q8b is provided between the amplifier side connection terminals P1a; P1b on the output side of the compensators U4a; U4b, and the transistors Q8a; Q8b. A signal delay variable resistor (SVR2a; SVR2b) is provided at the base end of the signal delay, and the output is delayed by a predetermined time by the signal delay variable resistor (SVR2a; SVR2b) and the switching transistors Q8a; Q8b to output the power. There is provided a wireless microphone receiver, characterized in that it is possible to eliminate the pop noise generated when.

Hereinafter, described with reference to the accompanying drawings, preferred embodiments of the present invention is as follows. 1 is a block diagram of a wireless microphone receiver according to the present invention, FIGS. 2 and 3 are circuit diagrams of a first receiving circuit and a second receiving circuit of the present invention, FIG. 4 is an audio circuit diagram of the present invention, and FIG. Power circuit diagram of the subject innovation, Figure 6 is a photograph of the use state of the subject innovation.

Referring to this, the wireless microphone receiver receives a dual channel frequency band and has a receiving circuit for each channel separately. Each receiving circuit is divided into a first receiving circuit shown in FIG. 2 and a second receiving circuit shown in FIG. 3. At this time, each receiving circuit is provided with reverse bias blocking diodes (D10a; D10b) for blocking the intrusion of the RF signal reverse bias of the other channel receiving circuit to prevent crosstalk between signals.

The components of each receiving circuit will be described with the flow of signals as follows. First, only a predetermined frequency band is filtered through the RF signals received through the antennas ANTA (ANTb) through the RF filters T1a, T2a; T1b, T2b. The filtered frequency band is low noise amplified by low noise amplifiers Q1a and Q1b for minimizing noise generated during the amplification process, and then filtered through RF filters T3a, T4a, T3b, and T4b. At this time, the reference frequency oscillated by the oscillators X1a; X1b is filtered through the oscillation frequency filters T7a, T8a; T7b, T8b, and the intermediate frequency together with the RF signal passed through the RF filters T3a, T4a; T3b, T4b. It is mixed by the mixers T5a and T5b. This intermediate frequency mixer T5a; T5b removes the carrier frequency from the RF signal to generate an intermediate frequency. The generated intermediate frequency is filtered through an intermediate frequency filter FL1a (FL1b) that removes unnecessary output and amplified through an intermediate frequency amplifier Q3a; Q3b. The amplified intermediate frequency is once again filtered through the intermediate frequency filters FL2a and FL2b and then applied to the automatic gain controllers U1a and U1b. Preferably, the automatic gain controller (U1a; U1b) is a LA1140 IC, and automatically adjusts the gain so that the output of the AF signal detected by the AF detector T6a; T6b is kept constant by receiving an intermediate frequency. It plays a role. In the receiving circuit of each channel configured as described above, a cathode is provided on the power input side (VCC, pin 12) of the automatic gain controllers U1a and U1b, and the oscillators X1a and X1b and the oscillation frequency filters T7a, T8a, T7b, and T8b. Reverse bias bias diodes D10a and D10b, each having an anode connected to the ground side thereof, are provided, and each diode D10a; D10b blocks the inverse bias of the RF signal moved along the receiving circuit of another channel. Play a role. Therefore, by preventing crosstalk between signals, the first receiving circuit and the second receiving circuit can be designed on the same printed circuit board as in the use state diagram of FIG. 6.

FIG. 4 illustrates an audio circuit up to terminals P1a and P1b connected to amplifiers by receiving an AF output generated by the automatic gain controllers U1a and U1b. First, the AF signal generated by the automatic gain controllers U1a and U1b is amplified while passing through the AF amplifiers U2a and U2b. At this time, the automatic gain controllers U1a and U1b separately generate mute outputs to remove the noise of the AF signal, which cancels the noise of the AF signal amplified through the mutes U3a, Q6a; U3b and Q6b. At this time, the detection resistors R31a and R31b and the capacitors C53a and C53b connected to the ground side of the automatic gain controller U1a and U1b are connected in parallel. The detection resistors R31a and R31b and the capacitors C53a and C53b pass only signals having a strength greater than or equal to a predetermined value, thereby stably operating the mutes U3a, Q6a; U3b and Q6b. In this way, by using the resistors R31a and R31b and the capacitors C53a and C53b in place of the conventional RSSI module, the size of the printed circuit board can be reduced in size and the production cost can be reduced.

On the other hand, the AF signal from which the noise is removed passes through the comparators U4a and U4b, and decompresses and restores a predetermined ratio compressed signal to cancel the noise by increasing the signal-to-noise ratio on the transmitter side. The generated audio signal is transmitted to the amplifier via terminals P1a and P1b connected to the amplifier. At this time, switching transistors Q8a and Q8b having an emitter connected to the output side of the comparators U4a and U4b and a collector connected to the ground, and a variable resistor for signal delay connected to the base end of the switching transistors Q8a and Q8b. SVR2a; SVR2b) is provided. The signal delay variable resistors SVR2a and SVR2b and the switching transistors Q8a and Q8b serve to delay the output for a predetermined time according to the resistance values of the variable resistors SVRa and SVRb. This is to remove the pop noise generated when the power is turned on, thereby eliminating the need for a conventionally complicated pop noise removing circuit, and thus, the size of the printed circuit board can be further reduced. Of course, production costs are also down.

FIG. 5 illustrates a power supply circuit of the present invention, and illustrates the use of a down converter U8 for receiving a 12V DC power supply and supplying a constant voltage of 9V to each IC. TP1a to TP4 shown in each circuit diagram in the drawing show terminals to which a 12V power input is connected.

As described above, the wireless microphone receiver of the present invention includes reverse bias diodes D10a and D10b for blocking reverse bias of RF signals between different receiving circuits, thereby receiving multiple channels of receiving circuits on a single printed circuit board. It can be accommodated, accordingly, there is an advantage that the production cost is reduced and the size of the receiver is reduced. In addition, instead of the RSSI module or the pop-noise suppression circuit, which has conventionally occupied a considerable area on the printed circuit board, the detection resistors R31a; R31b, the capacitors C53a; C53b, and the compensator connected to the automatic gain controllers U1a; U1b. The switching transistors Q8a and Q8b and the signal delay variable resistors SVR2a and SVR2b connected to the output sides of the U4a and U4b play a role, thereby significantly reducing the size of the printed circuit board and reducing production costs. There is an advantage.

As described above, according to the present invention, a reverse bias blocking diode that prevents reverse bias of an RF signal between receiving circuits can be provided to accommodate receiving circuits of multiple channels on the same printed circuit board without crosstalk. Detection resistors, capacitors, switching transistors, and signal delay variable resistors replace RSSI modules or pop-noise cancellation circuits, which occupy a significant area on the circuit board, significantly reducing the size of printed circuit boards and reducing production costs. A wireless microphone receiver can be provided.

Claims (3)

In a wireless microphone receiver for receiving RF signals of channels having different frequency bands and outputting them as audio signals through a speaker, and receiving circuits of each channel are separately provided, each receiving circuit includes an antenna (ANTa; RF filters (T1a, T2a; T1b, T2b) for filtering RF signals input through the RF signal, low noise amplifiers (Q1a; Q1b) for low noise amplification of the filtered RF signals, and amplification. Oscillators (X1a; X1b) for oscillating a reference frequency to remove carrier frequencies from the RF signal, and intermediate frequency mixers (T5a; T5b) for mixing carrier signals and the oscillation frequency to remove carrier frequencies. And intermediate frequency amplifiers Q3a and Q3b for amplifying the intermediate frequencies generated by the intermediate frequency mixers T5a and T5b, and detecting the AF signals at the intermediate frequencies to lower the intensity of the AF signals. Automatic gain controllers U1a; U1b for maintaining and blocking a signal having low sensitivity, and an AF amplifier U2a for amplifying the AF signals output from the automatic gain controllers U1a; U1b; U2b) and mutes (U3a, Q6a; U3b, Q6b) connected to the automatic gain controllers (U1a; U1b) to suppress noise by suppressing an input signal having no signal-to-noise ratio from the AF signal, and a transmitter side It includes a comparator (U4a; U4b) to increase the signal-to-noise ratio by extending the compressed signal in the, the anode on the ground side of the oscillator (X1a; X1b) on the power input side of the automatic gain controller (U1a; U1b) Reverse bias diodes D10a and D10b having cathodes connected to the power input terminals VCC of the gain controllers U1a and U1b are provided to block the intrusion of RF signal reverse bias from other channel receiving circuits. This can cause crosstalk between signals. Prevented by, a wireless microphone receiver, it characterized in that the receiving circuit to accommodate the different channels in a printed circuit board of the same. A detection resistor (R31a; R31b) and a capacitor (C53a; C53b) connected to the other side of the automatic gain controller (U1a; U1b) connected to the ground side are connected in parallel. And a resistor (R31a; R31b) and a capacitor (C53a; C53b) are passed through the automatic gain controller (U1a; U1b) only when the strength of the AF signal is greater than a predetermined value. 2. A switching transistor (Q8a; Q8b) is provided between the amplifier side connection terminals (P1a; P1b) on the output side of the compensators (U4a; U4b), and the base end of the transistors (Q8a; Q8b). A signal delay variable resistor (SVR2a; SVR2b) is provided, and the signal delay variable resistors (SVR2a; SVR2b) and the switching transistors (Q8a; Q8b) are output when the output is delayed for a predetermined time and is turned on. Wireless microphone receiver, characterized in that to eliminate pop noise.