1. Using DDS algorithm, the frequency step value can be up to 0.001HZ, good frequency stability. 2. This product can not only output 7.830Hz Schumann wave, but also increase the programmable frequency modulation technology, can be adjusted in the range of 0.001Hz - 200KHz frequency (can also be used as an ordinary programmable digital signal generator). 3. Digital crystal oscillator frequency reference, more stable, more anti-interference; 4. Power supply interface using DC5.5*2.1 interface, easy to use, USB terminal can be inserted into the power supply or USB charging head or other USB power supply device work. Schumann wave itself does not directly act on the sound or video products to improve the sound quality, but acts on the space environment, can relax the human body and mind, improve the human body's ability to perceive the sound and image, improve the human body's health and work efficiency, and alleviate psychological stress. Instructions for use: Take out the USB cable that comes with the product, connect the round hole end with the circuit board, and plug the USB end into the power bank or USB charging head or other USB powered devices to work. How to change the frequency: Input the frequency directly and press the lower left button to complete the setting For example, press [7][.] [8][3], then press [OK] to set to 7.83Hz, the default power-on output is 7.83Hz, and the setting range is 0.001-200KHz. Antenna waveform:sine wave interface Waveform:sine wave + square wave + inverted square wave (the lower left corner is the output interface, and the waveforms are output at the same time) Power supply interface:DC5.5*2.1 Supply voltage:5V Rated power consumption:Less than 1W Default frequency:7.83Hz Adjustment range:0.001HZ-200KHz Sine signal voltage amplitude:3V square wave signal Voltage amplitude:5V Colour:Green Material:PCB Package Contents: 1 * Schumann wave generator 1 * USB cable Only the above package content, other products are not included. Note: Light reflection and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.