A digital microphone is a digital microphone made using the principle of electromagnetic induction. Due to its sound quality, it was not widely used in professional fields until the 1960s. But it has a big drawback, which is that it is very fragile and easily damaged. Take windproof measures using this digital microphone. Otherwise, sudden damage to the digital microphone may occur. Of course, it cannot be used for outdoor pick-up work. The reason for this feature is structural. Ribbon microphones use thin aluminum strips instead of coils in dynamic microphones. When the aluminum rod vibrates in a magnetic field, it also induces an electric current. The length of this aluminum strip is about a few centimeters, the width is about 2-4mm, and the thickness is only a few micrometers. It is lightweight, so it can perceive and transmit the vibration characteristics of sound waves, thus having good sound quality, but it is also easily damaged.
A ribbon digital microphone does not have a diaphragm, and the
ribbon serves as both a diaphragm and a coil. Its acoustic
driving method is also different from the dynamic coil type,
which is a double-sided driving type. When the distance between
the sound wave and both sides of the aluminum strip is
different, a sound pressure difference will occur due to
different phases. Aluminum bars will vibrate according to the
sound pressure difference.
Capacitive digital microphone: It is currently one of the better
performing digital microphones. Its core is a capacitor. There
are three types: audio, radio frequency, and electret. Working
through capacitance changes. It mainly consists of diaphragm,
rigid plate, power supply, and load resistor. When the diaphragm
is subjected to pressure from sound waves and vibrates with
pressure and frequency, its working principle is to change the
capacitance between the diaphragms. At the same time, the charge
on the electrode plate undergoes a corresponding change, causing
a corresponding change in the current in the circuit, and there
is also a corresponding voltage output on the load resistance,
thereby completing the acoustic electric conversion.
Capacitive digital microphones have a wide frequency range, high
sensitivity, low distortion, and good sound quality, but they
have complex structures and high costs, and are often used for
high-quality broadcasting, recording, and sound reinforcement.
A wireless digital microphone is actually a small sound
reinforcement system. It consists of a miniature perm. Composed
of a miniature electret capacitor digital microphone, frequency
modulation circuit, and power supply. Wireless digital
microphones use frequency modulation methods to modulate
signals. The modulation signal is transmitted through a short
circuit and open circuit of a digital microphone. According to
regulations, its transmission frequency range is between 100MHz
and 120MHz. Every 2MHz is a channel to avoid mutual
interference.
Wireless digital microphones and receivers should be paired one
by one and used together. No errors are allowed. It is a
dedicated FM, but regular FM radios can also hear the sound of
wireless digital microphones, as long as the tuning frequency is
adjusted to the frequency of transmission.
Digital microphones are small in size, easy to use, have good
sound quality, are wireless, can move freely, and have low
transmission power. Therefore, they have been widely used in
classrooms, stages, television shooting, and other fields.
