The classic attenuator is a simple, passive product. Its main task is to qualitatively attenuate the signal without changing its shape. In the field of high frequencies, the universal attenuator can be used as a matching unit. In the traditional case, the product is presented in the form of a classic voltage divider. Capacitors and microcircuits are hidden in the case of the device. If it is necessary to reduce signals of different amplitude, then discrete switches or adjustable devices must be added to the overall circuit.
Description
Controlled attenuator is a universal simplex type patch cord. It is used in the case when you need to make the signal on the fiber-optic communication line lower. Such units are simply indispensable in local and backbone data transmission networks, as well as on cable television lines. Their use is justified in various measuring points. With this device, experts cancalibrate existing power meters, as well as determine the sensitivity of the receiver.
Attenuators are versatile products that can greatly attenuate an incoming signal with minimal return loss (maximum 70 dB). This effect is achieved due to design features. Wall attenuators are distinguished by the following parameters:
- Long service life.
- Optimal attenuation stability.
- Ease of use.
- Compact dimensions.
- High reliability.
- Minimum back reflection.
- Wide temperature range.
Classification
Despite the apparent simplicity, the characteristics of attenuators are usually divided into several categories. Experts identify a list of key parameters:
- Frequency range.
- Power and voltage.
- Total number of output levels.
- Variety of applied elements.
Depending on the level of input voltage, modern attenuators are high-voltage and low-voltage. The operating frequency range of products varies from light signals to direct current. Since attenuators are used by specialists in a fairly wide range of operating voltages, the element base extends from conventional resistors, coils and capacitors to fiber optic devices and microwaves.
Varieties
Experts often check attenuators, since only the operability of these products allows avoiding serious overloads in the used unit of receiving modules. On sale you can find universal devices that compare favorably with all analogues with a fixed attenuation index. But there are those models where the user can independently adjust all parameters.
In the first case, a specific glass filter, a doped LED or an air gap is presented. The product is present in the cable as an absorbing filter. A professional can build a special bend of the optical LED of the transmission cable. This category is most often mounted in the socket housing. The type of attenuator and its connectors can be any (most often it is SC).
Adjustable attenuation units are used in quality measurement equipment. To control the ratio, you can use the two most common options. In the first case, the master is given the opportunity to make mechanical adjustments to the air gap. The second option allows you to influence that part of the optical cable that is intended for signal transmission.
Basic types
Manufacturers are accustomed to using a special decoding of numbers, so you can quickly determine the purpose of the attenuators:
- Assemblies based on discrete radio elements.
- Verification setups and reference devices.
- Products that absorbenergy.
- Polarized.
- Electronically controlled attenuators.
- Limit models.
Checking and reference products are actively used by experts for a qualitative metrological assessment of operating attenuators. Limit models prevent signals below a set frequency from passing through the waveguide system.
Almost all units, except for fixed ones, can be easily controlled using various electronic circuits that have been repeatedly tested in the laboratory. Such products are simply indispensable in cases where manual adjustment remains unavailable for any reason.
Benefits
The numerous positive properties of optical attenuators have ensured their frequent use in the creation of high-quality fiber optic systems. Key benefits include:
- Easy and easy to install.
- Compact size.
- Two efficient fixed-type designs.
- Excellent operating temperature range for use in extreme environments (-65 to +80°C).
Standard designation
Absolutely all models of attenuators that operate in the radio range are indicated by a capital letter "D", followed by numbers. Due to this, specialists can quickly decipher the category andpurpose of the product. The numbers determine the brand of the unit. Classical optical products are marked with the combination "OD1".
Application
The input attenuator is the simplest and most affordable receiver node. Its design is distinguished by its simplicity and logic. Three resistors are used as the main parts, but in some cases there may be three capacitors, which are designed to qualitatively divide the signal. The most difficult task is to choose the damping parameter of the unit.
The official documents contain information that modern models of attenuators are able to effectively expand the dynamic range of receivers. But only experienced radio amateurs understand the fact that you should not delude yourself with this principle. Dynamic range consists of two key concepts that are quite different from each other. A conventional receiver is capable of receiving not only weak, but also strong signals. They necessarily fall within the bandwidth of the filter, which is related to the basic selection. In the event of a minimum gain, the receiver will simply overload.
If the user wants to receive weak signals from a particular station, then an attenuator can be used, but even he cannot guarantee that the result will be as expected. The main reason is powerful interference that negatively affects the high frequency path. In such a situation, rebooting the equipment cannot be avoided.
