The mini transmitter is highly integrated digital video transmission equipment that can realize wireless video transmission in mobile and NLOS (Non line-of-sight) conditions. With professional clothes and pinhole camera, it can be used in public security bureau or security department to finish covert missions (technical investigation and covert intelligence gathering). It can be also applied in emergency and evacuation, railway, marine and so on. We can use the mini transmitter with a specially designed multifunctional amplifier to meet the requirement of longer transmission range