Abstract: A sonar compensation transformer is added to a sonar transceiver circuit to btain calibrated optimum performance from a sonar transducer using ceramic rings by slightly modifying the voltage of the transducer while at the same time allowing the transmit circuit to operate without appreciable change.The sonar compensation transformer is an improvement upon a conventional sonar transceiver circuit containing a transformer winding connected in series with a diode switch with the outer bounding connections of the transformer winding and the diode switch connected to the transducer element while the connection to the sonar transceiver is from a connection tapped into the winding of the sonar transformer and the connection from the outer bound of the diode switch. The sonar compensation transformer is connected in with a primary winding placed in parallel with the diode switch.

Abstract: Musician controlled relative motion between a generally standard stringed musical instrument (such as a Spanish guitar) and a false body hinged to the generally standard stringed instrument permits versatile control by the musician of the tension in one or more strings to produce both vibrato sounds and/or sustained pitch changes (both higher and lower pitches). The invention eliminates limitations of prior art which employed relative motion between neck and body of an otherwise generally standard stringed musical instrument.