Briefly introduce 10 types of equipment composed of broadcast audio systems

There are mainly 10 types of devices used in broadcast audio systems, which are briefly described as follows:

1, the coordinator

(1) Sensitivity. Taking power as a reference point, the lower the sensitivity value, the better the effect.

(2) 50dB squelch. In order to achieve noise, the received signal strength is less than 50dB.50dB greater than the noise. The lower the signal strength, the better the performance.

(3) Signal to noise ratio. The signal-to-noise ratio is expressed by S/N. The higher the S/N ratio, the better. The stereo is greater than 65dB.

(4) Capture rate. The capture rate, sometimes called selectivity, is the ability to work under the influence of a given frequency station. The lower the capture rate, the better.

(5) Frequency response. Frequency response The appropriate frequency modulation range is performed in the range of 30 Hz to 15 kHz, and the lower the frequency response value, the better.

(6) Stereo separation. The stereo separation indicates the degree to which the tuner stereo decoder can isolate the left and right channels. The larger the value, the better.

(7) Squelch valve. It means that the squelch circuit ensures that the noise between the two stations is suppressed during tuning.

(8) Others. Such as frequency suppression, intermediate frequency suppression, false response, and so on.

2, preamplifier

The task of the preamplifier is to amplify various weak signals. The general considerations are: volume control, tone control, loudness control, and bandwidth control.

3, microphone

Microphones, also known as microphones, microphones, microphones or microphones, are transducers that convert sound into a signal. The factors considered are:

(1) Frequency response. Frequency response is the frequency response, the parameters that affect performance are:

a, frequency range.

b, rated frequency response.

c. Transient characteristics.

(2) Sensitivity. Sensitivity is an important parameter of the acoustic-electrical control capability. Its characteristics are:

a, open circuit sensitivity S.

b, the load sensitivity S,.

c, sound field sensitivity S,.

d, voltage sensitivity S.

(3) Impedance. The impedance of the microphone is divided into output impedance and load impedance. The output impedance is internal resistance, and the smaller the value, the better. The load impedance is the input impedance, and the larger the value, the better.

(4) Directionality. Directionality is also called directivity. It is characterized by unidirectionality, omnidirectionality and bidirectionality.

(5) Signal to noise ratio.

4, record player

The record player uses mechanical methods for sound signal recording. It consists of a turntable, an arm, a pickup, a stylus and an accessory. At present, such products are used less in engineering and will not be introduced here.

5, tape recorder

There are many occasions for the application of the recorder, and there are many varieties, but in general, it is divided into two types of disc type and cassette type recorders. The disc recorder is divided into desktop, vertical and portable. The cassette recorder is mono, stereo, stereo. In terms of technical and performance indicators, due to various varieties and various performance indicators, from the engineering point of view, the more important indicators have 1 signal to noise ratio; 2 frequency response; 3 harmonic distortion; 4 jitter rate; 5 sensitivity; Selective.

6, the speaker

Consider the speakers used from an engineering perspective.

7, laser record player

The laser player is also called a CD (Compact Disc) player, which is a product of photoelectric bonding. Its characteristics are mainly manifested in two aspects

(1) The electroacoustic index is high. The specific performance is 1 high signal-to-noise ratio (generally 90-130dB); 2 large dynamic range (accommodating large-scale music activities); 3 good separation; 4 small distortion; 5 frequency range; 6 small jitter rate.

(2) Operational aspects. Features panel buttons and remote control.

8, headphones

A headset, also known as an earpiece, is a device that converts audio electrical signals into sound waves. There are many kinds of it, if it is divided into electromagnetic, electric, voltage, and electrostatic according to the principle of transduction. If differentiated by conduction, there are all-guided and bone-guided.

If you use the way, there are head-mounted, plug-in, ear-hook.

If it is divided by performance, it is closed, semi-open, and fully open.

If the structure is divided into high-impedance headphones, low-impedance headphones.

From the application point of view, we consider the main performance of the headset. In general, consider 6 point 1 frequency response; 2 sensitivity; 3 rated impedance; 4 power; 5 working voltage; 6 intermodulation distortion.

9, the mixer

The mixer is an important device of the broadcast control center to transmit, process and distribute audio signals and monitor the output channels.

(1) Mixing console classification. There are many types of mixers, which can be divided into four types:

a. According to the type of program, it can be divided into music station and voice station.

b, according to the use of occasions can be divided into portable and fixed.

c. According to the output mode, it can be divided into mono, two-channel, stereo, four-channel and multi-channel.

d. According to the signal processing method, it can be divided into analog and digital.

(2) Function. The functions of the mixer mainly consider the following five points:

a, level and impedance distribution, the output impedance should be 1/5 of the load impedance.

b. Signal amplification and frequency equalization.

c, dynamic processing.

d, signal distribution and mixing.

e. Provide special effects.

(3) Application. Due to different places and objects, the functional requirements and scale of the mixing console are different. The products used in the actual application are 1 synchronous white station; 2 late sounding station; 3 external sound mixer; 4 outgoing mixer; 5 music station ; 6 transcription table; 7 mixed recording station, etc.

10, power amplifier

An amplifier that supplies signal power to a load is called a power amplifier. When the power amplifier is operating normally, the signal voltage and current are relatively large. Generally, the power amplifier stage 3, which is internally composed of three parts and which receives the input signal from the input signal from the preamplifier, generates an output current, and drives the driver stage of the power amplifier stage.