经典型
经典前置放大器有一个易于理解的概念。它基本上是一个归一化增益放大器,具有极高的输入阻抗和非常低的输入电容。
HBK 的传声器前置放大器坚固耐用,并针对各种环境操作条件进行了声学优化。我们的前置放大器的高输出电流能力能够在不衰减信号的情况下驱动极长的电缆,即使在测量高频时存在的高声压级也是如此。HBK CCLD和经典前置放大器设计适合我们的1/2英寸和1/4英寸传声器。
A condenser microphone must be combined with a preamplifier to provide impedance conversion, some filtering, and the capability to drive relatively long cables without significant signal degradation.
Our preamplifiers are designed in accordance with two principles, referred to as Classical Preamplifiers, and CCLD Preamplifiers. Each provide their own special set of features:
The classical preamplifier has an easy to understand concept. It is basically a unity gain amplifier with extremely high input impedance and very low input capacitance.
Despite its origin in the vibration transducer world, the Constant Current Line Drive (CCLD) principle is increasing in popularity in the area of sound and measurement applications. Different manufacturers market transducers using the CCLD principle under different names.
The benefit of CCLD is that the same wire is used for both the signal and the supply current. Using TEDS Class I even the TEDS data can be transmitted over that same wire (using a level controlled electronic switch as shown in the figure below).
Brüel & Kjær offer a large selection of robust and acoustically optimised preamplifiers that allow operation in a wide range of environmental conditions. The high output current capability of Brüel & Kjær preamplifiers allows the use of extremely long cables, even with high sound pressure levels present at high frequencies.
A CCLD input can be connected to both microphones and vibration sensors (and many other sensors with CCLD output). Due to the working principle the signal is superimposed on a DC voltage. This DC bias voltage is typically around 12 V. Bias drift (over temperature or time) will reduce the dynamic range.
Due to the lower DC supply voltage (typically 20 – 28 V DC compliance voltage out of the front-end), there is some limitation in the upper limit for a CCLD solution. Another limitation of CCLD solution is that only prepolarized microphones can be used and that CIC is not available.
This, however, in many practical applications is happily accepted to reap the benefits of CCLD: Ease of use and cheap cables!
* Acoustical means a tapered preamplifier house. Other preamplifiers have cylindrical houses
For further details of the range, availability, and price, please use the link below to get in touch with your local Brüel & Kjær representative.
This will bring together HBM, Brüel & Kjær, nCode, ReliaSoft, and Discom brands, helping you innovate faster for a cleaner, healthier, and more productive world.
This will bring together HBM, Brüel & Kjær, nCode, ReliaSoft, and Discom brands, helping you innovate faster for a cleaner, healthier, and more productive world.
This will bring together HBM, Brüel & Kjær, nCode, ReliaSoft, and Discom brands, helping you innovate faster for a cleaner, healthier, and more productive world.