Modulation-signal generator circuit, image display apparatus and television apparatus
A modulation-signal generator circuit generates a modulation signal having a time width corresponding to tone data that is input. The modulation-signal generator circuit includes an output section outputting the modulation signal and a control circuit. The output section is controlled so as to set the height value of the modulation signal to a predetermined height value during a first period in a period during which one modulation signal is output and is controlled so as to set the height value of the modulation signal to a height value higher than the predetermined height value during a second period. The control circuit sets a maximum time width which is available as the first period, and sets the maximum time width in accordance with a signal generated based on an instruction of a user or sets the maximum time width in accordance with a signal indicating the characteristics of the tone data.
1. An apparatus for generating a modulation signal whose height value and the time width thereof are controlled in accordance with an input value of luminance-tone data, said apparatus comprising:
a control circuit; and
an output section,
wherein the control circuit defines a maximum time width which is available as a time width of a first height value of the modulation signal and sets a predetermined value of luminance-tone data corresponding to the modulation signal whose first-height-value time width is controlled so as to be the maximum time width,
wherein the output section outputs, when an input value of the luminance-tone data is not more than the predetermined value, the modulation signal whose first-height-value time width is controlled so that the upper limit of the first-height-value time width is the maximum time width in accordance with the input value of the luminance-tone data, and the output section outputs, when the input value of the luminance-tone data is higher than the predetermined value, the modulation signal whose first-height-value time width is controlled to be the maximum time width and whose time width of a second height value, which is higher than the first height value, is controlled in accordance with a value which exceeds the predetermined value in a period which is different from a period in which the first height value is controlled, and
wherein the control circuit changes the maximum time width in accordance with a signal input to the control circuit and changes the predetermined value in accordance with the signal input to the control circuit.
2. An apparatus according to claim 1 , wherein the signal input to the control circuit includes a signal generated based on a user's instruction.
3. An image display apparatus comprising:
an apparatus to claim 1 ; and
an image display section having a plurality of display elements.
4. An image display apparatus according to claim 3 , wherein the display elements comprise an electron emission element and a fluorescent material which emits light when the fluorescent material is irradiated with electrons emitted from the electron emission element.
5. A television apparatus comprising:
a tuner for television broadcasting signals; and
an image display apparatus according to claim 3 , which displays an image based on a signal output from the tuner.