Abstract: The storage units and the output of an averaging type recursive or non-recursive digital filter are modified by input signal changes greater than a predetermined amount indicative of a step change to provide a rapid step response characteristic.

Abstract: A measuring instrument provides a reading only when a desired measurement is taken by making successive measurements and waiting until two successive measurements are within a predetermined low range, the measurements are above a predetermined floor range, and the difference between a reading and successive measurements exceed a predetermined high range.

Abstract: An FM tuner control circuit contains a digital frequency synthesizing control circuit, digital computer means including a microprocessor, a memory circuit, and a manual control circuit for digitally tuning the tuner to any desired FM station. The memory circuit includes a read-only memory containing programs for the microprocessor and a random-access memory in which a group of predetermined station frequencies can be stored. The control circuit also includes a call letter display circuit, a frequency scale pointer display circuit, a frequency display circuit, a manual tuning circuit, and remote control switches for the manual control circuit.

Abstract: A digital diagnostic system employs signature analysis for locating faults at the system, module, or circuit component level in electronic equipment. Predetermined correct signatures and diagnostic decision tree information for a particular device under test are stored in system memory. The diagnostic system exercises the device under test to generate signatures which are obtained at various predetermined test points and electronically compared with a stored signature. From the diagnostic decision tree information, a troubleshooting sequence is automatically established which leads directly to a faulty module or component. In-circuit microprocessor emulation may be utilized to generate one or more of the signature signals.

Abstract: An FM tuner control circuit contains a digital frequency synthesizing control circuit, digital computer means including a microprocessor, a memory circuit, and a manual control circuit for digitally tuning the tuner to any desired FM station. The memory circuit includes a read-only memory containing programs for the microprocessor and a random-access memory in which a group of predetermined station frequencies can be stored. The control circuit also includes a call letter display circuit, a frequency scale pointer display circuit, a frequency display circuit, a manual tuning circuit, and remote control switches for the manual control circuit.

Abstract: There is provided according to the invention a method and apparatus for eliminating or minimizing the error due to amplifier offset or drift error in an integrating dual slope analog-to-digital converter. The converter is provided with a switching and control arrangement whereby the integrating capacitor is charged for one-half of the predetermined charging time as a function of the sum of the levels of the unknown signal and the error signal. The integrating capacitor is charged for the remaining half of the predetermined time period as a function of the difference of the levels of the unknown signal and the error signal so that the capacitor reaches a level of charge which is a function of the level of the unknown signal substantially unaffected by the level of the error signal.