A solid-state imaging device is provided, which comprises unit pixel portions. The transceiver includes a TOSA whose housing is grounded with the FG and connected with the driver with a FPC board. Insulating material may be disposed between the side stakes, the exterior metal surface and the at least one fiber reinforced layer of fiber reinforced material. The estimated Doppler spread is generally proportional to a square root of the first ratio, and is scaled by a multiplicative factor that depends on whether the estimated function is an autocorrelation or autocovariance function. The magnitude of the differential signal output from the circuit can thus sustain in a predetermined range even if the magnitude of the supply voltage is lower than the minimum magnitude required by the conventional circuit.