Method for using a synchronous sampling design in a fixed-rate sampling mode

#The present application generally relates to apparatuses such as television signal processing apparatus, that process radio frequency signals. More specifically, the present application is particularly useful in integrated circuits that combine circuitry operating in a synchronous-sampling mode that must be adapted for use with a fixed rate sampling mode application.

#The present application generally relates to apparatuses such as television signal processing apparatus, that process radio frequency signals. More specifically, the present application is particularly useful in integrated circuits that must combine circuitry operating in a synchronous-sampling mode that must be adapted for use with a fixed rate sampling mode application.

#Modern signal processing apparatus typically include signal processing circuitry for processing a multitude of signal formats, such as NTSC, ATSC, QAM, or satellite signals. Such a signal processing apparatus typically includes various components such as a tuner for selecting a particular signal or channel from a plurality of signals or channels received by the apparatus. To process digital signals, such as ATSC or satellite signals, the signal processing circuitry, and in particular the tuner, must perform these functions with high-speed digital circuitry. Some digital signal processing apparatus operate in a synchronous-sampling mode, where the A/D converter takes samples coincident with the digital symbol locations. The digital symbols, and subsequently the sampling frequency are calculated by the demodulator and a rate control signal is output from the demodulator to control the sampling rate of the A/D. It is also possible to take samples using an A/D converter at a fixed time intervals.

#The above-mentioned and other features and advantages of this invention, and the manner of attaining them, will become more apparent and the invention will be better understood by reference to the following description of embodiments of the invention taken in conjunction with the accompanying drawings, wherein:

#FIG. 1 is a block diagram of a television signal processing apparatus according to an exemplary embodiment of the present invention;

#FIG. 2 a block diagram of an exemplary embodiment of digital signal processing circuitry utilizing an A/D converter operating according to a fixed rate sampling mode concurrently with subsequent signal processing circuitry operating according to a synchronous sampling mode;

#The exemplifications set out herein illustrate preferred embodiments of the invention, and such exemplifications are not to be construed as limiting the scope of the invention in any manner.

#Referring to FIG. 1, a block diagram of an exemplary embodiment of television signal processing apparatus 100 of FIG. 1 is shown. In FIG. 1, television signal processing apparatus 100 comprises signal receiving means such as signal receiving element 110, tuning means such as tuner 130, demodulation means such as demodulator 140, decoding means such as decoder 170, processing means and memory means such as processor and memory 180, audio amplification means such as audio amplifier 190, audio output means such as speaker 135, video processing means such as video processor 145, and visual output means such as display 155, a power supply 125 and a switch 115 responsive to the processor and memory 180. Some of the foregoing elements may for example be embodied using integrated circuits (ICs). For clarity of description, certain conventional elements of television signal processing apparatus 100 including control signals may not be shown in FIG. 1. According to an exemplary embodiment, television signal processing apparatus 100 may receive and process signals in analog and/or digital formats.

#Signal receiving element 110 is operative to receive signals including audio, video and/or auxiliary data from signal sources, such as radio frequency broadcast signal transmission sources, or cable television transmission. Signal receiving element 110 may be embodied as any signal receiving element such as an antenna, input terminal or other element.