What is the frequency of the IF current?
The industrial intermediate frequency generally refers to 400 Hz, the radio intermediate frequency refers to 465 kHz, and the FM band is about 10 MHz.
The intermediate frequency has two meanings:
First, when the frequency is divided. Medium frequency ( MF , Medium Frequency ) refers to the frequency range from 300KHz to 3000KHz , and most of them are AM stations. In the daytime, the propagation distance is short, and at night, since the ionospheric reflection signal can be utilized, it can be transmitted over long distances. However, it is more susceptible to interference from other waves.
The pitch of most natural instruments is in the mid-range. The place where vocal energy is most concentrated is 500-1000 Hz. The overtones of many natural instruments also fall mainly in the mid-range, such as guitar, and the overtones mainly fall in 2000-5000 Hz. The same is true of violas and cellos.
Second, according to its position and role in the circuit to divide: IF intermediate frequency (Intermediate Frequency) refers to a high-frequency signal obtained by frequency conversion. In order to be able to stabilize the amplifier operation and reduce interference. Usually receiver high-frequency signal to be changed to an intermediate frequency signal.
The image IF signal of the TV set is 38MHZ.
The intermediate frequency signal of the audio is 6.5MHZ.
The medium frequency signal of the medium and short wave radio is 465KHz.
The intermediate frequency of the FM radio is 10.7MHZ
Radio frequency refers to the transmission frequency, because some signals may not be suitable for direct transmission (the frequency is illegal, or the signal itself is not allowed). Therefore, to modulate the signal, the modulator itself needs a suitable oscillating signal, and the original signal is added to it. This oscillating signal is called a carrier, and the modulated carrier is included.
