System for converting number of scanning lines
Sampling frequency converting apparatus
Sample rate conversion system having interpolation function
Sampling frequency converter for converting a lower sampling frequency to a higher sampling frequency and a method therefor
Sample rate conversion system having interpolation function with phase locked clock
Sample rate converter
System and method for conversion of digital video signals
Apparatus for converting a signal of a first sample rate into a signal of a second sample rate
Sampling rate converter for signals having a non-integer sampling ratio
ApplicationNo. 957721 filed on 10/07/1992
US Classes:348/441, FORMAT CONVERSION341/61, Data rate conversion348/445, Conversion between standards with different aspect ratios708/313Decimation/interpolation
ExaminersPrimary: Groody, James J.
Assistant: Lee, Michael G.
Attorney, Agent or Firm
International ClassesH04N 011/20
AbstractA sample rate conversion system converts from an input sample rate stream having a predetermined input sample rate to an output sample stream having a predetermined output sample rate by interpolating output samples from the input samples using first and second approximate sample rate ratios. The system includes circuitry which selects a sequence of interpolation filters from among a set of filters, the sequences being defined by one of these approximate ratios, and circuitry which monitors the magnitude of the accumulated error introduced by the approximation. When this accumulated error becomes greater than a threshold, the system changes to use a further sequence of interpolation filters based on the other approximate ratio. The accumulated error changes in a positive sense with each successive sample while one of the two approximate ratios is used. The accumulated error changes in a negative sense with each successive sample while the other of the two approximate ratios is used. The system switches between these sample rate ratios to maintain the magnitude of the position error of the interpolated samples below a predetermined threshold value. A sample rate conversion system which converts a television signal in CCIR (601) format into a Phase Alternate Line (PAL) video signal is disclosed.