Input circuit for an HF-transmitting component

• US 20030218489A1
• Filed: 05/19/2003
• Published: 11/27/2003
• Est. Priority Date: 05/25/2002
• Status: Active Grant

• Current Assignee: Hydrometer Electronic GmbH
• Original Assignee: Diehl AKO Stiftung & Company KG
• Inventors: Sebald, Marc, Werner, Wolfgang, Zimmermann, Jurgen
• Granted Patent: US 6,885,256 B2
• Time in Patent Office: Days
• US Class Current: 327/290
• CPC Class Codes: H03B 2200/0008 Colpitts oscillator
• CPC Class Codes: H03B 5/368 the means being voltage variable capacitance diodes
• CPC Class Codes: H04B 1/0475 with means for limiting noise, interference or distortion H04B1/0483 takes precedence
• CPC Class Codes: H04L 27/12 Modulator circuits; Transmitter circuits

Abstract

An input circuit for an HF-transmitting component 1 of a battery-operated device for the transmission of a data signal aims to reduce the power consumption. For that purpose the fundamental frequency of a reference oscillator 5 is modulated with the digital data signal, the data rate being greater than 20 kchip/s. For smoothing of the modulated reference signal an amplitude limiter 11 and a band pass filter 15 are connected between the reference oscillator 5 and the HF-transmitting component 1.

Claims

1. An input circuit for an integrated HF-transmitting component of a battery-operated device for the transmission of a data signal, in which a reference oscillator is connected to one of the inputs of the HF-transmitting component, wherein that the fundamental frequency of the reference oscillator (5) is modulated with the digital data signal, wherein the data rate is greater than 20 kchip/s, and wherein an amplitude limiter (11) and a band pass filter (15) are connected between the reference oscillator (5) and the HF-transmitting component (1).

2. An input circuit according to claim 1, wherein the amplitude limiter (11) limits the amplitude of the frequency-modulated data signal to about +/−

600 mV.

3. An input circuit according to claim 1, wherein the band-pass filter (15) limits the band width of the frequency-modulated data signal to about 500 kHz.

4. An input circuit according to claim 1, wherein a prefilter (8) causes the digital data signal which is applied to the reference oscillator (5) to reduce the edge gradient of the data signal.

5. An input circuit according to claim 1, wherein that the digital data signal is applied to the reference oscillator (5) through of a modulation device (7) having a capacitance diode.

6. An input circuit according claim 1, wherein reference oscillator (5) is a Colpitts oscillator.

7. An input circuit according to claim 1, wherein the fundamental frequency of the reference oscillator (5) is lower than the transmission frequency of the HF-transmitting component (1).

8. An input circuit according to claim 7, wherein the fundamental frequency of the reference oscillator (5) is about 6.788 MHz.

9. An input circuit according to claim 7, wherein the transmission frequency of the HF-transmitting component (1) is 868.5 MHz.

10. An input circuit according to claim 1, wherein the data rate is in a range from about 50 to 120 kchip/s.

11. An input circuit according to claim 10, wherein the data rate is about 100 kchip/s

12. An input circuit according to claim 1, wherein the HF-transmitting component (1) and the reference oscillator (5) are switched on and off cyclically.

13. An input circuit according to claim 12, wherein the HF-transmitting component (1) and the reference oscillator (5) are switched on approximately every 4 s for 4 ms.