AM receiver
AssigneeSony Deutschland GmbH
InventorsMarkus Zumkeller, Carsten Merkle
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Abstract
An AM receiver with at least one IF filter with a fixed IF bandwidth comprises at least one downconversion stage (3, 4, 5) to shift the signal input thereto into an IF range (IF1) having a variable oszillation frequency (fLO1) which is adjustable to detune a wanted center frequency (fC1) of a wanted signal part (30) from a center frequency (fIF1) of said at least one IF filter so that an unwanted signal part (31b) adjacent to said wanted signal part (30) lies outside said fixed IF bandwidth.
Claims11
AM receiver comprising at least one IF filter with a fixed IF bandwidth, characterized by at least one downconversion stage (3, 4, 5) to shift the signal input thereto into an IF range (IF1) having a variable oszillation frequency (fLO1) which is adjustable to detune a wanted center frequency (fC) of a wanted signal part (30) from a center frequency (fIF1) of said at least one IF filter so that an unwanted signal part (31b ) adjacent to said wanted signal part (30) lies outside said fixed IF bandwidth.
AM receiver according to anyone of the preceding claims, characterized in that it is a digital shortwave receiver, in particular a Digital Radio Mondial receiver.
AM receiver according to anyone of the preceding claims, characterized in that said at least one IF filter is an analogue filter.
AM receiver according to anyone of the preceding claims, characterized in that said fixed IF bandwidht is 20 kHz.
AM receiver according to anyone of the preceding claims, characterized in that said unwanted signal part (31b) is detected by analyzing the power of FFT carriers outside the wanted signal part (30), BER fine tuning in a digital baseband processing or during optimization of an Automatic Gain Control voltage.
Method to process a received AM signal wherein the received and eventually preprocessed AM signal gets shifted at least once into an IF range (IF1), characterized by detuning a wanted center frequency (fC) of a wanted signal part (30) from a center frequency (fIF1) used during at least one IF filtering with a fixed IF bandwidth so that an unwanted signal part (31b) adjacent to said wanted signal part (30) lies outside said fixed IF bandwidth.
Dependencies are inferred from the claim text.