The principle of heart rate chest band is to measure the periodic changes of heart current or potential in skin through electrodes on both sides of heart rate band. This current is so small that it is easily disturbed. The first interference is other current noise signals in the skin, such as tense muscles, which also produce relatively large current noise. The way to prevent it is to put the heart rate band close to the heart, that is, the male is less than 2 cm below the nipple, or the female is at the lower edge of the breast. The second interference is that the displacement friction between the heart rate band electrode and the skin produces noise signals. This kind of interference is particularly obvious in sports, which is manifested in the fluctuation of numbers displayed on the heart rate meter. For this reason, the traditional heart rate hard belt is usually designed like a tire ripple at conductive rubber to increase frictional resistance and reduce movement. In the anti-interference ability of heart rate signal acquisition, the flexible fabric heart rate soft belt has great advantages compared with the hard one, because the flexible thin film electrode can perfectly fit the contour of the human chest and greatly increase the contact area between the electrode and the skin. Secondly, like all smooth surfaces, the thin-film electrode has a strong adsorption force on the skin after being wetted with water, which can be closely adsorbed on the skin, greatly reducing the interference of electrical signals generated by friction during exercise. The heart rate signal of the heart rate band should be transmitted to display terminals, such as heart rate watches, treadmills, treadmills and other display devices. Heart rate signals can be transmitted by being loaded on radio waves. According to frequency, radio waves can be divided into three categories. The first category is 5.3KHZ low frequency. This is the international heart rate transmission frequency. Most heart rate meters in gyms and some fitness equipment, such as treadmills with heart rate display, use this frequency to receive heart rate signals.