FILTER CENTRE FREQUENCY TEMPERATURE COMPENSATION BY ADJUSTMENT OF THE OPERATING FREQUENCY OF THE HOST SYSTEM

• US 20040023632A1
• Filed: 08/01/2002
• Published: 02/05/2004
• Est. Priority Date: 08/01/2002
• Status: Active Grant

• Current Assignee: Avago Technologies International Sales Pte Limited (Broadcom, Inc.)
• Original Assignee: Agere Systems Incorporated (Broadcom, Inc.)
• Inventors: Visee, Maarten
• Granted Patent: US 6,718,167 B2
• Time in Patent Office: Days
• US Class Current: 455/317
• CPC Class Codes: H04B 1/28 the receiver comprising at least one semiconductor device having three or more electrodes

Abstract

Electronic circuit including a frequency conversion device (4), an oscillator (6), a band-pass filter (8), and a controller (14), the oscillator (6) connected to the frequency conversion device (4), the frequency conversion device (4) connected to the band-pass filter (8),

the frequency conversion device (4) arranged to receive a first signal (S1) at a frequency (f_t), to transform the first signal (S1) into an intermediate signal (S2) at an intermediate frequency (f_i) by applying a selection frequency (f_loc) from the oscillator (6),

the band-pass filter (8) arranged to receive the intermediate signal (S2) and to perform a band-pass filtering at a centre frequency (f_bpf) and with a bandwidth (f_w), the centre frequency (f_bpf) equal to the intermediate frequency (f_i) at a predetermined working temperature of the band-pass filter (8), and the controller (14) capable to receive data indicative of a shift of the centre frequency (f_bpf) due to a temperature deviation of the band-pass filter (8) from the predetermined working temperature and to control the selection frequency (f_loc) of the oscillator (6) for changing the intermediate frequency (f_i) to follow the shift of the centre frequency (f_bpf).

Claims

1. An electronic circuit adapted for being coupled to a system having a frequency signal conversion device, a local oscillator and, a band-pass filter, said local oscillator coupled to said frequency signal conversion device, said frequency signal conversion device coupled to said band-pass filter,

said frequency signal conversion device arranged to receive a first signal at a first frequency (f_t), to transform said first signal into an intermediate signal at an intermediate frequency (f_i) by applying a first selection frequency (f_loc) received from said local oscillator,

said band-pass filter arranged to receive said intermediate signal and to perform a band-pass filtering at an intrinsic centre frequency (f_bpf) and with a bandwidth (f_w), said intrinsic centre frequency (f_bpf) being substantially equal to said intermediate frequency (f_i) at a predetermined working temperature of said band-pass filter wherein the electronic circuit comprises:

a controller arranged to receive data indicative of a shift of said intrinsic centre frequency (f_bpf) due to a temperature change of said band-pass filter from said predetermined working temperature and to control said first selection frequency (f_loc) of said local oscillator for changing said intermediate frequency (f_i) of said intermediate signal to follow said shift of said intrinsic centre frequency (f_bpf).

2. Electronic circuit according to claim 1, further comprising a base-band signal conversion device and a base-band oscillator, said base-band oscillator coupled to said base-band signal conversion device, said base-band signal conversion device coupled to said band-pass filter,

said base-band signal conversion device arranged to receive said intermediate signal at said intermediate frequency (f_i), to transform said intermediate signal into a base-band signal at a base-band frequency by applying a second selection frequency (f_bb) received from said base-band oscillator,

wherein

said controller is arranged to control said second selection frequency (f_bb) of said base-band oscillator for changing said base-band frequency of said base-band signal to follow said shift of said intrinsic centre frequency (f_bpf).

3. Electronic circuit according to claim 1, wherein said base-band signal at said base-band frequency is a second intermediate signal at a second intermediate frequency.

4. Electronic circuit according to claim 1, wherein said electronic circuit comprises a temperature sensor adjacent to said band-pass filter for producing a temperature-related signal (Δ

V), and said controller is arranged to use said temperature-related signal (Δ

V) as said data indicative of said shift of said intrinsic centre frequency (f_bpf).

5. Electronic circuit according to claim 4, wherein said electronic circuit further comprises a signal processing unit and a switch, said switch connected to said base-band conversion device and said temperature sensor for switching between said base-band signal and said temperature-related signal (Δ

V), said switch further connected to said signal processing unit for passing said base-band signal or said temperature-related signal (Δ

V) to said signal processing unit.

6. Electronic circuit according to claim 1, wherein said electronic circuit further comprises memory means for storing temperature-related calibration data, said memory means connected to said controller, said controller being arranged to fetch said calibration data from said memory means and to use said calibration data to control said first selection frequency (f_loc).

7. Electronic circuit according to claim 2, wherein said electronic circuit further comprises memory means for storing temperature-related calibration data, said memory means connected to said controller, said controller being arranged to fetch said calibration data from said memory means and to use said calibration data to control said first selection frequency (f_loc) and said second selection frequency (f_bb).

8. Electronic circuit according to claim 1, further comprising a base-band signal conversion device, a signal processing unit, and a base-band oscillator, said base-band oscillator coupled to said base-band signal conversion device, said base-band signal conversion device coupled to said band-pass filter, said base-band signal conversion device further coupled to said signal processing unit, said signal processing unit connected to said controller,

said base-band signal conversion device arranged to receive said intermediate signal at said intermediate frequency (f_i), to transform said intermediate signal into a base-band signal at a base-band frequency by applying a second selection frequency (f_bb) received from said base-band oscillator (9),

wherein

said signal processing unit is arranged to sample said base-band signal to establish energy distribution level characteristics within said base-band signal and to pass said energy distribution level characteristics to said controller (14).

9. Electronic circuit according to claim 8, wherein said controller (14) is arranged to evaluate said energy distribution level characteristics, and to control said first selection frequency (f_loc) of said local oscillator for changing said intermediate frequency (f_i) of said intermediate signal and said second selection frequency (f_bb) of said base-band oscillator for changing said base-band frequency of said base-band signal to follow said shift of said intrinsic centre frequency (f_bpf) in dependence on said energy distribution level characteristics.

10. Electronic circuit according to claim 8, wherein said electronic circuit further comprises memory means, said memory means connected to said controller (14), said memory means comprising correction data relating said energy distribution level characteristics to said first selection frequency (f_loc) of said local oscillator and said second selection frequency (f_bb) of said base-band oscillator, and said controller being arranged to fetch said correction data from said memory means and to use said correction data to control said first selection frequency (f_loc) and said second selection frequency (f_bb).

11. Electronic circuit according to claim 1, wherein said controller is a wireless medium access controller.

12. Electronic circuit according to claim 1, wherein said electronic circuit is part of either a transmitter or a receiver.

13. In an electronic circuit having a frequency signal conversion device arranged to receive a first signal at a first frequency (f_t) and to transform the first signal into an intermediate signal at an intermediate frequency (f_i) by applying a first selection frequency (f_1oc) received from a local oscillator and having a band-pass filter that performs a band-pass filtering of the intermediate signal at an intrinsic center frequency (f_bpf),

a method comprising the steps of:

receiving data indicative of a shift of the intrinsic center frequency (f_bpf) due to a temperature deviation of the band-pass filter from a predetermined working temperature, and

controlling the first selection frequency (f_loc) of the local oscillator for changing the intermediate frequency (f_i) of the intermediate signal to follow the shift of the intrinsic center frequency (f_bpf).