A speech coder that performs analysis-by-synthesis coding of a signal determines gain parameters for each constituent component of multiple constituent components of a synthetic excitation signal. More particularly, the ultrasonic holographic imaging system may use a reference wave introduced on the side of a thin detector that acts as a wave guide; to introduce the reference wave to a liquid-to-gas interface or alternatively, from the topside of the detecting surface through a liquid-to-liquid interface. In some embodiments, the second function is simply the second input signal to the XOR function. The coating includes in cross-section a fin with a bulbous region. The plasma display device, which has a plasma display panel and a circuit unit for supplying a driving signal to the panel, includes a cavity-type heat dissipator having a plate which is located near a portion of the circuit unit to dissipate heat generated at the circuit unit, and wings which are affixed to the plate and extend from the edges of the plate inward.