The **APLS1642.5-R** is a specific surface-mount electronic component, typically categorized as a **Dielectric Bandpass Filter**. These components are widely used in wireless communication to allow specific frequencies to pass while rejecting interference. --- ### 1. General Specifications The part number follows a nomenclature used by manufacturers (often related to brands like Walsin or similar RF component specialists). Here is a breakdown of the typical technical profile: | Parameter | Typical Value | | :--- | :--- | | **Component Type** | Dielectric Bandpass Filter | | **Center Frequency ($f_0$)** | 1642.5 MHz | | **Bandwidth** | Usually ± 15-20 MHz | | **Mounting Type** | Surface Mount (SMD/SMT) | | **Impedance** | 50 $\Omega$ (Standard) | | **Application** | Inmarsat, Satellite Communications | --- ### 2. Key Electronic Characteristics #### A. Center Frequency ($f_0$) The "1642.5" in the part number indicates a center frequency of **1642.5 MHz**. This frequency is specifically allocated for mobile satellite services (MSS), particularly used by the **Inmarsat** satellite constellation for uplink/downlink communications. #### B. Insertion Loss This represents the energy lost as the signal passes through the filter. For a dielectric filter of this class, insertion loss is typically low (between **1.5 dB to 3.0 dB**), ensuring signal integrity. #### C. Attenuation (Rejection) This component is designed to "clean" the signal. It provides high rejection for frequencies outside the passband, protecting the receiver from: * Cellular interference (LTE/5G) * Image frequencies * Local oscillator leakage --- ### 3. Physical Construction * **Material:** It is made of high-Q ceramic dielectric materials. * **Structure:** Usually consists of multiple coupled resonators inside a ceramic block. * **Terminations:** Silver or gold-plated pads for soldering onto a PCB. --- ### 4. Typical Applications The APLS1642.5-R is found in the RF Front-End (RFFE) of the following devices: 1. **Satellite Terminals:** Handheld satellite phones or portable data terminals. 2. **GPS/GNSS Augmentation:** Specialized high-precision positioning systems. 3. **IoT Modules:** Satellite-linked sensors for remote monitoring (Agri-tech, Maritime). ---