Feature: 1. Adopt advanced digital audio signal processing (dsp) and phase-locked loop (pll) fm modulation to make the sound more lifelike, the performance is more stable, and the long-time work does not shift the frequency 2. LCD display is more intuitive and accurate, with extremely low power consumption and low noise 3. Possess the functions of searching and storing radio stations, built-in 30 digital volume adjustment knobs, which can easily complete the operation 4. Automatically close the data memory before power off, and automatically switch the speaker/headphone output 5. Quartz crystal frequency is stable, no more frequency drift when temperature changes 6. Professional dsp audio signal analysis and processing, automatically mute the long time of fm signals with no signal or weak noise floor, far away from traditional fm broadcast signals or the annoying rustle when there is no or weak signal 7. Digital incremental rotary encoder to adjust volume and frequency, good in use, possess accurate positioning, stable and durable, 360° rotation without dead angle 8. Support serial communication control, computers or devices using other MCU control modules have complete serial functions Specification: Item Type: FM Receiver Module Material: PCB Use: Output Power: 500mw(driving earphones), 3w x 2(driving speakers) Frequency Range: 50hz-18khz Receiving Frequency Range: Close Campus Radio: 87.0mhz-108.0mhz Open Campus Broadcast: 76.0mhz-108.0mhz Noise Equivalent: 3030db Supply Current: Maximum Capacity: 1000ma, Minimum Capacity: 60ma (for reference only) Channel: Stereo : Power 1. The module has a Micro USB interface and can be powered by a computer USB. : Antenna The FM_ANT port is used to connect an FM antenna. In order to better receive FM signals, it is recommended to connect a 75cm-long whip antenna. : Headphone/speaker output This module comes with a 3WX2 channel audio power amplifier. If you need a speaker to connect to the speaker port, it is recommended to use a 4Ω/3W speaker. If the earphone is inserted, the audio is automatically switched to the earphone channel, and the speaker channel is automatically closed. Volume adjustment Turn the VOL encoder (the one on the right) to adjust the volume, and the LCD screen displays the volume level. Frequency adjustment Turn the Frequency encoder (the encoder on the left) to adjust the receiving frequency, and the LCD screen displays the current frequency. Automatic channel search Short press the Frequency encoder to automatically search for local radio stations. At the same time, the LCD screen displays the current frequency, and it stops when a valid radio station is found. Mute Short press the VOL knob down to switch mute/non-mute. Automatic squelch switch Long press the VOL knob down to switch on or off the automatic squelch function, the LCD display subtitles ON means to turn on the automatic squelch, and OFF means to turn off the automatic squelch. Automatic squelch threshold (threshold) adjustment (effective when the automatic squelch switch is turned on) Long press the Frequency knob down to enter the automatic squelch threshold adjustment interface. Rotate the VOL knob to adjust the automatic squelch threshold according to the specific usage. The adjustment range is 0-31. The larger the value, the higher the threshold and the weaker the signal. Easy to be muted. The opposite is true. : Connect to the serial port (no need to connect to the serial port for control) The module reserves a TTL level serial port control interface. The communication between the TTL serial port and this module needs to be connected to the module's UART_RX, UART_TX and GND (the corresponding position on the PCB is marked), and the external MCU (microcontroller) or computer serial port can be used to send instructions to control the module.. Package List: 1 x Module2 x Nut2 x Gasket Note: The corresponding ports of the module (marked on the PCB board) ‑ and + are respectively connected to the negative and positive terminals of the power supply (battery). It is recommended to use a battery or other stabilized power supply for the power supply. It is not recommended to use switching power supplies without filters (such as mobile phone chargers, mobile power supplies, and other switching power supplies), otherwise the interference generated by the power supply will affect the normal operation of this module. The normal working voltage of this module is 3.0‑5.0V, and the power supply voltage should not exceed this range.