Abstract: Methods and systems for tracking movements of participants in a market research study, for example, outside retail establishments, are provided. The methods and systems employ portable monitors carried on the persons of the participants to gather location data.

Abstract: Methods and systems for measuring and gathering data relating to publication usage by participants in publication readership studies. Some methods and systems employ portable monitors carried by participants of the studies along with publications fitted with various devices, such as piezoelectric transducers, RFID tags and others devices and circuits.

Abstract: Novel strip chart recorders and strip chart recording paper are provided which are cooperable so that the recorder detects the proximity of a terminal edge of the paper, so that the recorder can signal this occurrence to the user enabling him to insert a new supply of strip chart paper in the recorder to avoid the loss of data. The recorder also cooperates with the strip chart paper to determine when paper is absent from the recorder, for example, when it has been exhausted, thereupon to signal this further occurrence to the user and take steps to avoid damage to the recorder which can result through its operation in the absence of paper in the recorder mechanism.

Abstract: For medical examination purposes, an ultrasonic imaging device in which ultrasonic pulses are transmitted into a body of a patient and reflected therefrom. The reflected pulses are converted from ultrasonic to electrical signals by electro-acoustic elements which are then amplified by a time-gain-controlled device and converted for display on a CRT by a scan converter. Amplification of the time-gain-controlled device is controlled by an output voltage produced by a control voltage generator. The generator includes circuitry for automatically delaying the amplitude varying characteristics of the output voltage with time.