Integer Wavelets for Displaying Gray Shades in RMS Responding Displays

Abstract

Abstract-A large number of gray shades can be displayed in rms responding displays by using integer wavelets. The technique is demonstrated by displaying 64 gray shades in a twisted nematic liquid crystal display. We have reduced the hardware complexity of the display drivers by adding a few analog multiplexers that are common to a large number of stages (one for each output) in the drivers. A simple controller was implemented in a low cost complex programmable logic device.Index Terms-Gray shades, liquid crystal displays (LCDs), matrix addressing, multi-line addressing (MLA), wavelets.

Scanning Matrix Displays With Wavelets

“…The third display is driven by modified slant wavelets to demonstrate that complexity of the controller does not depend on the complexity of the wavelets and just the data bits are adequate (not necessary to take the orthogonal transform of data) and the supply voltage is lower than that of multi-line successive approximation technique [6]. The fourth is based on multi-line addressing [3] while the fifth display is driven by line-by-line addressing [7] to demonstrate the capability and advantages of wavelets for a large number of gray shades. Hardware complexity of the driver circuit is a design parameter and it depends on the number of nonzero elements in the orthogonal matrix.…”

“…Hardware complexity of the driver circuit is a design parameter and it depends on the number of nonzero elements in the orthogonal matrix. For example; drivers that are capable of applying 1 of 8 voltages can be used as row drivers and column drivers along with some analog multiplexers for both line-by-line [7] and multi-line [3] implementation of the wavelets based addressing technique. Comparison of these techniques with other techniques for displaying a large number of gray shades viz.…”

“…Comparison of these techniques with other techniques for displaying a large number of gray shades viz. amplitude modulation [10], pulse height modulation [11] and successive approximation (multi-line) [12] as well as successive approximation line-by-line [13] can be found in references [3]- [7]. Detailed analysis of supply voltage and its comparison with other techniques, response time measurements and hardware implementation can be found in these references.…”

“…A wavelets-based technique [2] was proposed to display gray shades in SID'05. A large number of gray shades can be displayed by using wavelets [3]- [6], and the hardware complexity of the drivers depends on the number of wavelets that are used to select the rows simultaneously in the matrix display [4]. Drivers that are capable of applying 1-of-8 voltages to rows and columns of the matrix displays are adequate to display 128 gray shades.…”

Design and implementation of a wavelet‐based addressing technique (WAT)

“…Although the supply voltage and the number of time intervals are comparable to that of the successive approximation technique when the number of gray shades is 16, the wavelet technique has a smaller number of time intervals and lower supply voltage when the number of gray shades is greater than 16. 7 About 30% savings in supply voltage over successive approximation techniques can be achieved when the matrix in Eq. (16) is used to scan the display.…”