1. Basic relationship between signal strength and receiving sensitivity
To measure the receiving sensitivity of two-way radio equipment, we must first understand the close connection between signal strength and receiving sensitivity. Receiving sensitivity is essentially the minimum signal strength that the equipment can detect and effectively process. Signal strength is usually expressed in microvolts (μV) or decibel milliwatts (dBm).
In an ideal environment, when a weak RF signal enters the receiving end of the equipment, if the signal strength is lower than the receiving sensitivity of the equipment, the equipment will not be able to demodulate and decode it correctly, and thus cannot restore the original information. For example, in a laboratory environment, a signal generator is used to send a gradually weakening signal to the equipment. When the equipment begins to have bit errors or cannot demodulate the signal, the signal strength at this time is an intuitive reflection of the receiving sensitivity.
2. Key parameters and test methods
The key parameters for measuring receiving sensitivity include bit error rate (BER) and signal-to-noise ratio (SNR). The bit error rate refers to the ratio of the number of erroneous code elements to the total number of code elements in data transmission. Generally speaking, when the bit error rate is lower than a certain value (such as 1×10⁻⁵), the corresponding signal strength is the receiving sensitivity. The signal-to-noise ratio reflects the relative strength of the signal and the noise. In order to accurately measure the receiving sensitivity, there are two common test methods. One is to use a professional RF signal generator and spectrum analyzer to send signals to the device under test by precisely controlling the signal strength, frequency and modulation mode, and monitor the output signal quality of the device to determine the receiving sensitivity. Another method is to use a standard signal source in an actual communication environment, test under different distances and interference conditions, and determine the receiving sensitivity by analyzing the bit error rate and quality of the received data.
3. Factors affecting receiving sensitivity
The receiving sensitivity of two-way radio equipment is affected by many factors. The first is the performance of the antenna. The gain, efficiency and matching degree of the antenna are directly related to the signal strength received by the device. A high-gain antenna can enhance the signal reception capability, but if the antenna does not match the input impedance of the device, it will cause signal reflection and reduce the receiving sensitivity. The second is the RF front-end circuit inside the device, including low-noise amplifiers (LNA), filters and mixers. The noise coefficient of LNA has an important influence on the overall receiving sensitivity. A lower noise coefficient can improve the amplification ability of weak signals, thereby improving the receiving sensitivity. In addition, the electromagnetic environment in which the equipment is located, such as the strength and frequency of external interference sources, will also affect the receiving sensitivity.
4. The importance of receiving sensitivity in practical applications
The receiving sensitivity is of vital importance in the practical application of Two-way radio equipment. In terms of communication distance, a higher receiving sensitivity means that the equipment can receive weak signals sent from a longer distance, thereby expanding the communication coverage. For example, in outdoor expeditions, if the communication equipment between team members has a higher receiving sensitivity, good communication can be maintained even in areas with a long distance and complex terrain. In terms of communication quality, receiving sensitivity directly affects the reception effect of the signal. During the signal transmission process, due to various factors, the signal is attenuated. Equipment with high receiving sensitivity can better capture and process these attenuated signals, reduce signal loss and bit errors, and ensure clear and stable communication.
