Circuit arrangement for demodulating signals

• US 20030048131A1
• Filed: 08/23/2002
• Published: 03/13/2003
• Est. Priority Date: 08/28/2001
• Status: Active Grant

• Current Assignee: NXP B.V. (NXP Semiconductors NV)
• Original Assignee: Koninklijke Philips Electronics N.V. (Koninklijke Philips N.V.)
• Inventors: Kohsiek, Cord-Heinrich
• Granted Patent: US 6,677,816 B2
• Time in Patent Office: Days
• US Class Current: 329/315
• CPC Class Codes: H03D 3/002 Modifications of demodulators to reduce interference by undesired signals H03D3/248 takes precedence

Abstract

In a circuit arrangement for demodulating signals, particularly frequency-modulated signals, in which a limiter, to whose input the signals to be modulated can be applied, is followed by a demodulator from whose output the demodulated signals can be derived, the outputs of the demodulator and the limiter are connected to a respective input of a mixer whose output is connected to the input of the limiter via a low-pass filter.

Claims

1. A circuit arrangement for demodulating signals, particularly frequency-modulated signals, in which a limiter, to whose input the signals to be modulated can be applied, is followed by a demodulator from whose output the demodulated signals can be derived, characterized in that the outputs of the demodulator (5) and the limiter (4) are connected to a respective input of a mixer (9) whose output is connected to the input of the limiter (4) via a low-pass filter (7).

2. A circuit arrangement as claimed in claim 1, characterized in that the output of the limiter (4) is connected to the one input of the mixer (9) via a delay device.

3. A circuit arrangement as claimed in any one of the preceding claims, characterized in that the limit frequency of the low-pass filter (7) is below the frequency band of the signals to be demodulated.

4. A circuit arrangement as claimed in any one of the preceding claims, characterized in that the signal to be demodulated is an intermediate frequency signal which can be applied via a bandpass filter (3).