Abstract: A receiver requiring only a single IF SAW filter and IF amplifier receives signals in both analog format and in digital format, such as the NTSC, PAL and SECAM analog television signal formats and the ATSC and DVB digital television signal formats. IF signals from the IF amplifier are sub-sampled to digital signal form and are processed by respective analog format and digital format processors. Control circuitry responsive to the presence of certain unique components of the signals in analog format and digital format determine which of the analog format and digital format processors is producing valid data and selects the valid data to be utilized. In a television receiver, the unique components of the signals may include carrier signals, synchronization signals, pilot signals and symbol timing, and valid data is applied to a television display.

Abstract: A method and apparatus for recovering an information carrier which has been transmitted as a sub-carrier in the lower VSB spectral region of a television signal. The invention utilizes a spectral inversion method to shift the data carrier frequency from the normal VSB spectral region to a spectral region normally associated with video information in a standard television signal. The data carrier is then recovered using a standard video demodulator and provided to a data utilization circuit, such as a QPSK demodulator.

Abstract: Information processing system, for use with a source of carrier waves modulated with audio information, includes in respective audio channels a demodulator and for recovery of the audio information and track-and-hold amplifiers. Separate circuits are provided for detecting carrier drop-outs and impulse noise occurrences. The output of the detecting circuits is utilized to control the operation of the track-and-hold amplifiers to effect a masking of these occurrences. Signal de-emphasis is accomplished in each channel by means of two separate filters respectively arranged to operate on the input and output signal of the track-and-hold amplifier to minimize noise input to the track-and-hold amplifier.