The RBW filter is also referred to as the window function.įor this calculation to be accurate, a power (rms) averaging or sample detector must be used. The window bandwidth is the equivalent noise bandwidth of the RBW filter used. Where P ch is in milliwatts and FFT bins are in dBm. The power of a given channel is calculated by In a digital spectrum analyzer, calculating channel power is the process of integrating FFT bins over the specified channel bandwidth. P adj and P ch are measured in milliwatts and represent the channel power measured in the adjacent and main channel bandwidths. A measure of the adjacent channel power to the channel power, or ACP ratio (ACPR) can be simplified as, The ability of an SA to measure ACP-dominantly the dynamic range- is also limited by these same performance degrading factors within the SA. Mainly, phase noise, intermodulation distortion (IMD), and the noise level of transmitter or receiver technology. Signal energy from the carrier signal may leak into an adjacent channel due to a combination of effects. So, the ACP measurement performed by an SA may also reveal nonlinear conditions of a transmitter, receiver, or device. The nonlinear nature of most radio electronics active components leads to spectral regrowth that occurs in the adjacent channels surrounding the channel of interest. Organizations, such as the Federal Communications Commission (FCC) has developed mandates that prevent the majority of consumer and industrial electronics generating interference- beyond a small acceptable amount- to other frequencies.įor these reasons, while designing and testing a new technology, or evaluating a current radio system, being able to measure the signal energy that disperses, or leaks, into the surrounding channels is valuable in maintaining the standards and regulations. For this reasons, guard bands that separate the channels are also described in the channel definitions.

As communications hardware is not ideal, transmitted and received signal energy tends to disperse around the carrier signal frequency. These channels have a consistent center frequency and bandwidth. In-house Repair and Calibration ServicesĬhannel power of an FM broadcast band Adjacent Channel PowerĪdvanced telecommunication standards allocate slices of spectrum into known channels.EMC Near-field Probe Set with 40 dB Wideband Amplifier.Directional Coupler - 6 GHz – ZHDC-16-63-S+.Directional Coupler – 2 GHz – ZFDC-10-5-S+.

What is channel setting