Abstract: In a peak detection system having a variable gain amplifier (VGA), a counter is initialized and a countdown is triggered. Each time a qualified peak is detected, the counter is re-initialized. If the countdown is completed, the VGA gain is updated. This method can be used to boost amplifier gain that is too low to generate a qualifying threshold, even while overlooking short periods of very low output.

Abstract: A digital peak detection system digitizes analog signals and provides absolute values to a series of one cycle delays, and to a sequence of comparator stages. Each digital sample is parallel compared to a number of preceding samples equal to the number of active comparator stages. Control signals activate comparator stages to determine sample comparison window length, including lengths exceeding the number of samples between recorded peaks. Peak detection is optimized using a variable gain amplifier whose gain is updated based upon amplitude difference between actual and desired peak samples. When sample amplitudes are smaller than a qualifier threshold, a countdown timer increases amplifier gain after lapse of a programmed time without detecting a qualified pulse. Gain is also updated when the analog to digital converter saturates. Initial gain values can be programmed, and gain stored at the end of a servo mode for future use in reducing gain control loop convergence time.

Abstract: A method and related system for use with a disk drive are disclosed for adjusting the current level emanating from a read/write head during recording of data onto a disk to compensate for differences in read/write head and disk relationships. Also, a method and related system are disclosed for determining the optimum slimming constant to be utilized to minimize data pulse peak shifts to compensate for differences in read/write head and disk relationships.

Abstract: A method and apparatus for increasing the amount of data capable of being stored in a magnetic storage device is disclosed. Basically, a magnetic characteristic of the disk to head interface is measured at several locations on the disk. The frequency for writing and reading the data is optimized in terms of the required resolution and the magnetic measurement. The read and write modes are then varied, based upon the optimized frequency, such that data is written on the disk at a frequency substantially equal to the optimized frequency and read from a disk having data recorded at the optimized frequency.

Abstract: A transistor test circuit provides for the selection of preferably three widely differing test frequencies for testing transistors normally having respectively relatively small, intermediate and large frequency gain-bandwidth product characteristics. These test frequencies are each much greater than the assumed normal cut-off frequency of the transistors to be tested thereby, and preferably only a fraction of the frequency at which the current gain of normal transistors would decrease to one. The test circuit is designed to form a linear amplifier circuit with the transistor under test and is provided with an automatic base drive control circuit which provides a substantially fixed predetermined DC collector current, despite wide variations in the current gain between different transistors being tested.

Abstract: In combination with a meter movement having a pointer movable over a variable value indicating scale having numbered variable value indicating marks forming respective scale segments having substantially different compression or expansion ratios and representing progressively increasing variable values over the entire extent of said segments, a meter control circuit comprising respective amplifiers for controlling the variation of pointer movement over said respective segments of said scale, each of the amplifiers being capable of producing an output which reaches a maximum possible output level when the signal fed to the input thereof is of a value which is to move the pointer of said meter movement to the uppermost point of the associated segment of the scale, means for summing the outputs of said respective amplifiers and feeding the same to said meter movement.