Abstract: A circuit pack self-testing system adapted to carry out tests on circuit pack electronic devices. The self-testing system executes various test programs in a test suite, and stores a historical record from previous test suites. At the beginning of each test suite, a temporary record for test results is initialized. As the system progresses through the various test programs, the test programs update the temporary record.

Abstract: A multipurpose bus connects subsets of intercommunicating modular circuit packs in a complex electrical system. An individual one of the subsets may use the bus leads to transport signals differently from the other subsets. Each of the subsets of the circuit packs is selected to use the bus in particular time intervals. The subset, thus selected, uses the bus leads the way its own protocol governs during those particular time intervals and otherwise ignores the bus.

Abstract: An FSK demodulator of the differential type is arranged to provide two versions of an input FSK signal that, relative each other, (1) have a linear phase shift versus frequency characteristic and (2) are phase shifted by 90 degrees at a center frequency halfway between the upper and lower FSK frequencies. The linear phase shift is provided by an N sample delay element, while a constant phase shift circuit which includes a K factor gain element provides the 90 degree phase shift. By virtue of this arrangement, the demodulator characteristics can be adaptively varied and the demodulator tuned simply by changing the value of K. A similar adaptive technique is applied to a threshold detector arranged to position a threshold midway between the extremes of an input signal.

Abstract: An FSK demodulator of the differential type is arranged to provide two versions of an input FSK signal that, relative each other, (1) have a linear phase shift versus frequency characteristic and (2) are phase shifted by 90 degrees at a center frequency halfway between the upper and lower FSK frequencies. The linear phase shift is provided by an N sample delay element, while a constant phase shift circuit which includes a K factor gain element provides the 90 degree phase shift. By virtue of this arrangement, the demodulator characteristics can be adaptively varied and the demodulator tuned simply by changing the value of K. A similar adaptive technique is applied to a threshold detector arranged to position a threshold midway between the extremes of an input signal.

Abstract: There is disclosed a microcomputer having access sequence timing tailored to the requirements of a particular user. The device is arranged with a register for holding a parameter corresponding to a desired access cycle of the microcomputer. The register is adapted to receive from a user, either during manufacture, or during the execution of instructions, any desired parameter. Once the parameter is loaded into the register it will serve to control the cycle time of the microcomputer until such time as the parameter is changed by the user. Provision is made for changing the parameter on an instruction-by-instruction basis so that every instruction may have an independent execution time.

Abstract: Microcomputers are typically designed having a cycle time during which peripheral devices are accessed. This cycle is subdivided such that during a device access certain signals sequentially are activated to control the flow of data to or from the device over a set of special purpose leads. There is disclosed an arrangement for use when the device cannot respond within the allotted cycle for controlling the device access so that multiple successive cycles are used for a single device access. In this manner the microcomputer's speed is independent from the device response speed.