Unbalanced splitter- A multiple-output splitter that has unequal insertion loss or attenuation between the input port and each of the output ports. While splitters are generally considered to be flat-loss devices, in reality there is slightly more loss at higher frequencies than at lower frequencies. Passband- The specified operating frequency range of a splitter - for example, 5 MHz to 1002 MHz - over which the insertion loss is approximately equal at all frequencies. Splitter isolation is measured between any two of a splitter’s output ports, with all other ports terminated. Isolation- A measure of the attenuation of RF power between any two of a splitter’s output ports, when all other ports are properly terminated in the splitter’s characteristic impedance. A splitter’s insertion loss is measured between the input port and each of the output ports (with unused ports terminated). For example, a balanced two-way splitter has 10log 10(2) = 3.01 dB of insertion loss between the input port and each output port, and a four-way splitter has 10log 10(4) = 6.02 dB of insertion loss between the input port and each output port.įigure 3. For a balanced splitter, the theoretical insertion loss is defined mathematically as L dB= 10log 10(N), where L dBis the loss in decibels, and N is the number of output ports. Insertion loss- A reduction of RF power, expressed in decibels, between a splitter’s input port and each of its output ports (see Figure 3). Flatness can be degraded if unused ports are left unterminated. What is the total end-to-end insertion loss through these two combined splitters?īefore moving on, let’s take a quick look at definitions of some other common terminology applicable to splitters in general.Īdditional (or excess) insertion loss- Real-world splitters have somewhat higher insertion loss than what is calculated with the formula in the definition for “Insertion loss.” That additional or excess insertion loss is on the order of 0.5 dB to 1 dB (for a total insertion loss of 3.5 dB to 4 dB in a two-way splitter), and is caused by losses in the splitter’s internal transformers’ ferrite-core material and their very small gauge wire windings.īalanced splitter- A multiple-output splitter that has equal insertion loss or attenuation between the input port and each of the output ports.įlatness- A measure, in decibels, of amplitude-versus-frequency within the splitter’s passband. What’s the end-to-end insertion loss of this pair of splitters from input port to input port? The answer is at the end of the article.įigure 2. To get you thinking about that, consider the pair of back-to-back two-way splitters connected as shown in Figure 2. There is some “it depends” when it comes to the combined power, though. Here, RF signals from two sources can be applied to the two input ports (Ports 2 and 3 in Figure 1), and will appear at the single output port (Port 1 in Figure 1). In this usage, what were previously the splitter’s two output ports are now input ports, and the original input port is now the output port. However, the RF power level at each output port is approximately half of what it was at the input port.Īs well, a two-way splitter can be a power combiner. In the case of a balanced two-way splitter (more on “balanced” in a moment), when a radio frequency (RF) signal is applied to a splitter’s input port (Port 1 in Figure 1), the signal appears at equal amplitudes and with the same phase at each of the two output ports (Ports 2 and 3 in Figure 1). If you’ve ever wondered just how a two-way splitter works, grab a cup of coffee and read along!Ī splitter is a power divider. They’re part of the circuitry inside of some distribution passives such as taps and even other splitters! For example, a four-way splitter comprises a two-way splitter feeding a pair of two-way splitters. Those simple passive devices can be found on towers, in headends, hubs, the outside distribution network, and the subscriber drop. Two-way splitters have been used by the cable industry for decades.
0 kommentar(er)
