What is passive intermodulation?
Passive intermodulation (PIM) is a pernicious and destructive phenomenon for cellular network operators. PIM shows up as a set of unwanted signals created by mixing two or more strong RF signals. Mixing generally produces the sum and difference frequencies of the two transmit signals F1 and F2.
How do you calculate intermodulation product?
The order of the intermodulation product depends on how many input signals are mixed and which harmonics of each of those input signals have mixed. Second-order and third-order intermodulation products are defined as follows. 2 f 1 + f 2 = f 6 f 1 + 2 f 2 = f 7 2 f 1 − f 2 = f 8 2 f 2 − f 1 = f 9 .
How can passive intermodulation be reduced?
Use the cables provided or recommended by the base station vendor. Ensure that the antennas are specified to be low-PIM as well. Some Linearization algorithms can remove all these causes of Passive Inter-Modulation by characterizing the non-linearities and removing the products in the receive path.
What is 3rd order intermodulation?
3rd order intermodulation products (D3 and D4) are the result of nonlinear behavior of an amplifier. Near saturation, each additional dB of input power results in proportionally less output power going into the amplified carriers and proportionally more output power going into the unwanted intermodulation products.
What causes passive intermodulation?
PIM comes from two or more strong RF signals mixing in a non linear device. These non linear devices, or junctions, occur in improperly tightened, damaged, or corroded connectors or in damaged antennas. Rusty components, such as mounts and bolts, are also suspect when hunting for sources of PIM.
What is intermodulation distortion in amplifier?
Intermodulation Distortion can occur when two or more signals are mixed through a non-linear amplifier device. Each of the tones interacts with one another, producing altered (or modulated) amplitudes. Thus, it is termed Intermodulation Distortion because it is between harmonic frequencies.
What causes intermodulation?
Intermodulation is caused by non-linear behaviour of the signal processing (physical equipment or even algorithms) being used. The same nonlinear system will produce both total harmonic distortion (with a solitary sine wave input) and IMD (with more complex tones).
What is intermodulation interference?
Transmitter produced intermodulation interference is the result of one or more transmitters impressing a signal in the non-linear final output stage circuitry of another transmitter, usually via antenna coupling. The intermod product frequency is then re-radiated from the transmitter’s antenna.
What causes intermodulation distortion?
What is a PIM solution?
A Product Information Management (PIM) solution provides a single place to collect, manage, and enrich your product information, create a product catalog, and distribute it to your sales and eCommerce channels.
What is intermodulation in RF design?
Intermodulation is a phenomenon of combining undesired frequency components within an active system or from an external source. Combination of two or more signals will create another signal which may fall into another frequency band of the system and cause interference to the system.
What is the definition of passive intermodulation ( PIM )?
PASSIVE INTERMODULATION (PIM) PIM OVERVIEW: \\ Multitone intermodulation distortions (also referred to as Passive InterModulation or PIM) are caused by the nonlinear behavior of devices when two or more signals are present at the input. \\ In linear devices, the output is linearly proportional to the input.
What makes passive intermodulation a non linear effect?
The use of ferromagnetic metals, like iron, nickel and steel can give rise to passive intermodulation. These metals show magnetic hysteresis effects when energy is applied. This means that the resulting signal level is dependent, even to a small degree on input level. Hence this is a non-linear effect.
How are intermodulation products calculated in a calculator?
The calculator calculates IMD (Intermodulation) products based on two fundamental frequencies. In the same way IMD products can be found for more than two frequency inputs.
What kind of metal is used for passive intermodulation?
The use of ferromagnetic metals, like iron, nickel and steel can give rise to passive intermodulation. These metals show magnetic hysteresis effects when energy is applied. This means that the resulting signal level is dependent, even to a small degree on input level.