U.S. Philips Corporation

Koninklijke Philips Corporation N.v.

Gerardus C M Gielis

Rudy J Van De Plassche

Alphons A M L Bruekers

Eduard Ferdinand Stikvoort

Adrianus Sempel

Adrianus W M Van Den Enden

In a receiver, a tuner (TUN) converts a reception signal (Srf) to an intermediate-frequency signal (Sif). An adjustable frequency converter (AFRC) converts the intermediate-frequency signal (Sif) to an input signal (Sin) for a filter arrangement (FIL) which is capable of providing various frequency responses (Hfil , Hfil ) associated with different transmission standards. The adjustable frequency converter (AFRC) and the filter arrangement (FIL) may form part of an integrated receiver-circuit (IRC) suitable for many different transmission standards. The tuner (TUN) may provide the intermediate-frequency signal (Sif) at any one of various different intermediate frequencies (IF , IF ). For any intermediate frequency (IF ,IF ), the adjustable frequency converter (AFRC) can be adjusted in such a way that the filter arrangement (FIL) receives the input signal (Sin) in a frequency range (FR) which is suitably located with respect to its frequency responses (Hfil , Hfil ). Thus, the adjustable frequency converter (AFRC) allows the use of any one of various different intermediate frequencies and, therefore, allows the use of relatively cheap standard-specific tuners. Thus, it allows relatively cost-efficient implementations.

Multi-standard reception

In a receiver for receiving a modulated carrier (MC) having asymmetrical sidebands (USB,LSB), for example, a TV signal, a synchronous demodulator (SDEM) derives a vectorial baseband signal (VB) from the modulated carrier (MC). A filter (FILT) filters the vectorial baseband signal so as to compensate for the sideband asymmetry, for example, by means of a Nyquist slope. Thus, the sideband asymmetry is compensated at baseband frequencies, rather than at an intermediate frequency, which allows a better quality of reception.

Reception of modulated carriers having asymmetrical sidebands

To demodulate a quadrature input signal (S,) (for example, frequency shift) a demodulation unit (DEM) is used, comprising a PLL (P) having a complex mixer (M) and a controlled oscillator (V). Normally, a limiter has to be used to keep the loop gain independent of the amplitude of the quadrature input signal. In the PLL, a divider (DEL) is coupled between the mixer (M) and the oscillator (V) to divide the two mixed components (S,, S,) of the quadrature signal supplied by the mixer.

Growing community of inventors

Eindhoven, Netherlands

Gerardus C M Gielis