A classic attenuator is a simple, passive product. Its main task is to attenuate the signal qualitatively 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 device case. If it is necessary to reduce signals with different amplitudes, then discrete switches or adjustable devices must be added to the general circuit.
Description
The controlled attenuator is a universal simplex type connecting cord. It is used when it is necessary 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 at various measuring points. Using such a device, specialists can calibrate existing power meters, as well as determine the sensitivity of the receiver.
Attenuators are universal 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 differ in the following parameters:
- Long operational term.
- Optimum signal attenuation stability.
- Ease of use.
- Compact dimensions.
- High degree of reliability.
- The minimum indicator of back reflection.
- Wide temperature range.
Classification
Despite the apparent simplicity, the characteristics of attenuators are usually divided into several categories. Experts highlight a list of key parameters:
- Frequency range.
- Power and voltage.
- The total number of output signal levels.
- A variety of elements used.
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 microwave.
Varieties
Experts often test attenuators, since only the performance of these products avoids serious overloads in the used receiver module assembly. 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 the 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 absorption filter. A professional can build a special bend of the optical LED of the transmission cable. This category is most often mounted in a socket housing. The type of attenuator and its connectors can be any (most often it is SC).
Units with adjustable attenuation are used in high-quality measuring equipment. To control the coefficient, you can use the two most common options. In the first case, the master is given the opportunity to make mechanical amendments to the air gap. The second option allows you to act on the part of the optical cable that is designed to transmit the signal.
Main types
Manufacturers are used to using a special decoding of numbers, so you can quickly determine the purpose of the attenuators:
- Units that are based on discrete radio elements.
- Verification installations and reference devices.
- Products that absorb energy.
- Polarizing.
- Electronic attenuators.
- Limit models.
Verification and reference products are actively used by experts for high-quality metrological evaluation of existing attenuators. Limit models prevent the passage of signals through the waveguide system whose frequency is below the established indicator.
Almost all units, except fixed ones, can be easily controlled using various electronic circuits that have been repeatedly tested in laboratory conditions. Such products are simply indispensable in cases where manual adjustment for some reason remains unavailable.
Benefits
Numerous positive properties of optical attenuators ensured their frequent use in the creation of high-quality fiber-optic systems. The main advantages include the following options:
- Ease and simplicity of installation.
- Compact size.
- Two effective versions of fixed-type devices.
- An impressive range of operating temperatures, due to which the product can be used in extreme conditions (from -65 to +80 ° C).
Standard designation
Absolutely all attenuator models that operate in the radio range are indicated by a capital “D”, followed by numbers. Due to this, specialists can quickly decipher the category and purpose of the product. The numbers indicate the brand of the unit. Classical optical products are marked with the combination “OD1”.
Application
The input attenuator is the easiest and most affordable receiver unit. Its design is distinguished by its simplicity and logic. Three resistors are used as the main parts, but in some cases three capacitors may be present, which are designed to qualitatively divide the signal. The most difficult task is to select the unit attenuation parameter.
Official documents contain information that modern attenuator models can effectively expand the dynamic range of receivers. But only experienced hams understand the fact that you should not flatter yourself with this principle. The dynamic range consists of two key concepts that differ significantly from each other. An ordinary receiver is capable of receiving not only weak, but also strong signals. They necessarily fall into the filter pass-through strip, which is related to the basic selection. In the event of a minimum gain, the receiver will simply reboot.
If the user wants to receive weak signals from a specific station, then an attenuator can be used, but even he cannot guarantee that the result will meet expectations. The main reason is the powerful interference that negatively affects the high frequency path. In such a situation, a hardware reboot cannot be avoided.