Abstract: A system in which drooping of the video levels due to leakage currents and proper DC bias level is addressed by providing a charge into the video signal to offset the leakage currents and to provide DC bias. To determine the leakage current level, measurements are made measuring the voltages of the syncs and the blanking intervals. To determine the DC bias, a measurement is made of the sync. Over a series of video lines these measurements are averaged. If the average is below the desired level, a charge is provided via a current source to the incoming signal. By having the current source provide charge during each video line, droop is reduced and the proper DC bias is provided.

Abstract: A system in which drooping of the video levels due to leakage currents and proper DC bias level is addressed by providing a charge into the video signal to offset the leakage currents and to provide DC bias. To determine the leakage current level, measurements are made measuring the voltages of the syncs and the blanking intervals. To determine the DC bias, a measurement is made of the sync. Over a series of video lines these measurements are averaged. If the average is below the desired level, a charge is provided via a current source to the incoming signal. By having the current source provide charge during each video line, droop is reduced and the proper DC bias is provided.

Abstract: A video decoder in which 1) resolution quality can be improved for a given bit count analog-to-digital converter, 2) a lower bit count analog-to-digital converter can be used with substantially similar quality or 3) a combination of improved resolution quality with a lower bit count analog-to-digital converter can be done. In the preferred embodiment, a DC bias is added to the video signal after the sync portion of the composite signal has been received and prior to the active video being received. This bias is then removed after the end of the active video period. By applying this bias, the DC voltage level of the video signals is actually reduced, so that the full scale value of the analog-to-digital conversion process can also be reduced. Thus, compared to using an unbiased signal, increased A/D converter resolution is obtained. In an alternative embodiment, the sync portion can be biased upwardly during the front porch and then be returned during the back porch.

Abstract: A video decoder in which the video source clock is generated entirely in the digital domain is disclosed herein. By creating a virtual version of the source clock in a numeric oscillator, the amount of noise in the system is substantially reduced. Furthermore, by transferring the digitized video signal, sampled with an asynchronous crystal clock, into the source clock domain, the accuracy of the brightness (amplitude) and color (phase) information can be greatly enhanced.

Abstract: Video decoder systems in which both the analog-to-digital converter and the composite decoder are driven by the stable sample clock, such as a crystal source. The outputs of the composite decoder are provided to a source rate converter, having an output that is provided to a digital output formatter. The digital output formatter is driven by the output clock, which may be locked to the source clock if desired. The output clock is developed by a clock generator which may be one of several different types, including a fractional N synthesizer, a direct digital synthesizer or a puncture clock.

Abstract: A display FIFO memory management system and method includes a programmable FIFO emulator for emulating a drain and fill time of the display FIFO memory to automatically predict a number of register entries remaining in the display FIFO memory at each predefined clock cycle. A programmable timer/counter has programmable precision to accommodate varying bandwidths of display screen display modes and is used to determine the number of entries remaining so that the emulator can accommodate varying screen display modes. A FIFO controller controls the timing of fetching display data from memory to fill the display FIFO memory based on the prediction of the number of remaining register entries in the display FIFO by the programmable emulator.

Abstract: A multiple pipeline memory controller has a plurality of two stage pipeline processors dedicated to separately process real time video capture and display refresh input request signals. A separate pipeline processor processes non-real time input signals. The multiple pipeline design reduces memory access latency and improves throughput of data in display FIFO memory to effect improved resolution. The multiple pipeline memory controller can be integrated in a video graphics controller (VGC).

Abstract: A display FIFO memory management system and method includes a programmable FIFO emulator for emulating a drain and fill time of the display FIFO memory to automatically predict a number of register entries remaining in the display FIFO memory at each predefined clock cycle. A programmable timer/counter has programmable precision to accommodate varying bandwidths of display screen display modes and is used to determine the number of entries remaining so that the emulator can accommodate varying screen display modes. A FIFO controller controls the timing of fetching display data from memory to fill the display FIFO memory based on the prediction of the number of remaining register entries in the display FIFO by the programmable emulator.

Abstract: A method of processing audio signals is comprised of reading samples of digitally stored audio signals from a first source memory, performing a bit block transfer (BitBLT) of the samples to a register of an arithmetic and logic unit (ALU), reading an array of coefficient signals (coefficients), performing a BitBLT of the coefficients to a register of the ALU, operating on the bit block transferred samples and coefficients together and storing resulting samples in a destination memory, whereby the stored resulting samples can be further accessed for audio reproduction, further processing, permanent storage or transmission.