Industry consulting
Explanation of technical terms related to wireless microphone for audio accessories
1、 Squelch
When no signal is received or the signal is weak, the receiver of the wireless microphone for audio accessories will automatically cut off the output signal to avoid output noise. This function is called squelch. If there is no mute function or the mute function is poor, the speaker will emit noise. The noise will affect the sound quality, destroy the on-site atmosphere, and even damage the sound reinforcement equipment.
2、 Dead point
Also called dead zone. During the moving process of the wireless microphone for audio accessories, the signal received by the receiver will change in strength due to different distances, relative positions or barriers. At some positions within the normal use distance, too weak signal will make the noise circuit in the receiver act and cut off the output signal; After leaving this position, it can receive and output normally. This position is called the dead point or dead zone.
3、 Diversity reception
The wireless microphone receiver of audio accessories can receive signals from the same wireless microphone from two antennas, and select a strong signal through the internal circuit. This method can greatly eliminate the reception dead zone and avoid mute or dead point noise. There are two ways of diversity reception: antenna diversity and medium amplifier diversity.
In the antenna diversity mode, there are two receiving antennas, a set of control circuits and a set of receiving circuits. When the receiving signal is weak during operation, the control circuit will automatically switch to use another antenna.
In the medium amplifier diversity mode, in addition to two antennas and a set of control circuits, there are two complete sets of receiving circuits that work at the same time. The control circuit tracks and switches, and outputs a better audio signal. This method is better than the previous one because it tracks strong signals at any time, but the circuit is complex and the cost is high. This kind of diversity is often called double tuning, true diversity, etc.
4、 Multichannel
The carrier frequency of wireless microphone for general audio accessories is fixed and cannot be changed by users during use. Because wireless microphones transmit sound signals through radio waves, when there are external signals with the same or close carrier frequency in the working environment, interference will occur, reducing the receiving distance of the receiver, making output noise, or even failing to receive the microphone signal.
5、 Signal-to-noise ratio
It means that the receiver receives a signal of a specified strength (generally 60dB μ 5) The ratio of the original audio signal to the noise signal in its output signal is expressed in decibels (dB). The higher the value, the purer the signal, and the better the machine performance.
6、 Receiving sensitivity
In radio or walkie talkie, reception sensitivity refers to the minimum RF signal size required to be input when the receiver outputs a signal with a specified signal-to-noise ratio. The smaller the value, the higher the receiver sensitivity. In wireless microphones, it should be represented by the value of the input RF signal when the receiver is critically quiet, because when the input signal is lower than the quiet noise point and the receiver is in a quiet state, the signal is not output.
7、 RF output power
The signal energy transmitted to space by the wireless microphone transmitter of audio accessories is usually expressed in milliwatts (mW), generally between 5 and 50mW.
8、 Effective working distance
The maximum distance that the wireless microphone of audio accessories can normally transmit signals. Most of the parameters indicated on general products are in open ground or under ideal conditions. Because the actual transmission distance of the wireless microphone is affected by the actual environment, it cannot be accurately marked. Only indicators in open land or ideal conditions can provide reference and be compared with each other.
In fact, to measure the transmission capacity of the wireless microphone, the transmission power and the receiving sensitivity at critical squelch should be considered. After these two indicators are converted into the same unit, the greater the difference, the farther the effective working distance under the same environment. Combined with whether the receiver is of diversity type and which diversity mode it is, the effective transmission distance of different products can be estimated and compared clearly. In general, the effective range of diversity receiver is larger than that of non diversity receiver, and the receiver of intermediate amplifier diversity is larger than that of antenna diversity receiver.
When no signal is received or the signal is weak, the receiver of the wireless microphone for audio accessories will automatically cut off the output signal to avoid output noise. This function is called squelch. If there is no mute function or the mute function is poor, the speaker will emit noise. The noise will affect the sound quality, destroy the on-site atmosphere, and even damage the sound reinforcement equipment.
2、 Dead point
Also called dead zone. During the moving process of the wireless microphone for audio accessories, the signal received by the receiver will change in strength due to different distances, relative positions or barriers. At some positions within the normal use distance, too weak signal will make the noise circuit in the receiver act and cut off the output signal; After leaving this position, it can receive and output normally. This position is called the dead point or dead zone.
3、 Diversity reception
The wireless microphone receiver of audio accessories can receive signals from the same wireless microphone from two antennas, and select a strong signal through the internal circuit. This method can greatly eliminate the reception dead zone and avoid mute or dead point noise. There are two ways of diversity reception: antenna diversity and medium amplifier diversity.
In the antenna diversity mode, there are two receiving antennas, a set of control circuits and a set of receiving circuits. When the receiving signal is weak during operation, the control circuit will automatically switch to use another antenna.
In the medium amplifier diversity mode, in addition to two antennas and a set of control circuits, there are two complete sets of receiving circuits that work at the same time. The control circuit tracks and switches, and outputs a better audio signal. This method is better than the previous one because it tracks strong signals at any time, but the circuit is complex and the cost is high. This kind of diversity is often called double tuning, true diversity, etc.
4、 Multichannel
The carrier frequency of wireless microphone for general audio accessories is fixed and cannot be changed by users during use. Because wireless microphones transmit sound signals through radio waves, when there are external signals with the same or close carrier frequency in the working environment, interference will occur, reducing the receiving distance of the receiver, making output noise, or even failing to receive the microphone signal.
5、 Signal-to-noise ratio
It means that the receiver receives a signal of a specified strength (generally 60dB μ 5) The ratio of the original audio signal to the noise signal in its output signal is expressed in decibels (dB). The higher the value, the purer the signal, and the better the machine performance.
6、 Receiving sensitivity
In radio or walkie talkie, reception sensitivity refers to the minimum RF signal size required to be input when the receiver outputs a signal with a specified signal-to-noise ratio. The smaller the value, the higher the receiver sensitivity. In wireless microphones, it should be represented by the value of the input RF signal when the receiver is critically quiet, because when the input signal is lower than the quiet noise point and the receiver is in a quiet state, the signal is not output.
7、 RF output power
The signal energy transmitted to space by the wireless microphone transmitter of audio accessories is usually expressed in milliwatts (mW), generally between 5 and 50mW.
8、 Effective working distance
The maximum distance that the wireless microphone of audio accessories can normally transmit signals. Most of the parameters indicated on general products are in open ground or under ideal conditions. Because the actual transmission distance of the wireless microphone is affected by the actual environment, it cannot be accurately marked. Only indicators in open land or ideal conditions can provide reference and be compared with each other.
In fact, to measure the transmission capacity of the wireless microphone, the transmission power and the receiving sensitivity at critical squelch should be considered. After these two indicators are converted into the same unit, the greater the difference, the farther the effective working distance under the same environment. Combined with whether the receiver is of diversity type and which diversity mode it is, the effective transmission distance of different products can be estimated and compared clearly. In general, the effective range of diversity receiver is larger than that of non diversity receiver, and the receiver of intermediate amplifier diversity is larger than that of antenna diversity receiver.
