1,DSP + PLL,the frequency is more stable,the frequency will not change with the environment to a frequency drift.2,without any adjustment to bring the of DIY beginners.3,the frequency can be continuously adjusted within a specified range.4,with a microphone input and speaker volume can be controlled via digital potentiometer.5,audio input volume can be adjusted via a digital potentiometer.6, power can be adjusted continuously (non-linear) between the maximum power of 0.5W to 7W.7, the power output is good harmonic suppression network, the output spectrum cleaner8, frequency and volume have power failure protection, you do not need to set the !Now the transmitter to make a brief introduction:control panel components: mainly by M8 Series MCU and LCD display and keypad.transmitter board components: digital FM transmitter chip + 9018 + 2SC3355 + 2SC2851 + 2SC1971 four high frequency power amplification and power conditioning components.Input voltage: 12V DCthe input current: approximately 1.0Athe audio signal: Maximum input Vpp less than 1Vmicrophone type: cylinder microphone or microphonepower output: 0.5W-7W adjustable6, the output impedance: 507, the operating frequency: 76M-108MHz8, frequency step: 0.1MHz9, distortion: 0.03% to 0.1%a, board size: transmitting plate: 100 x 60mm, Dashboard: 55 x 36mmb, launch distance: more than 5KM (provided that the open area transmit antenna height above the surrounding buildings erected height of 10 )c, stereo separation: more than 63dbcolour:blueMaterial:Metal+pcPackage Contents:1 * 7W FM stereo PLL FM transmitter1 * Lcd Screen