Control device for telephone station and acoustic headset usable in said telephone station

• US 20030007631A1
• Filed: 03/09/2001
• Published: 01/09/2003
• Est. Priority Date: 05/25/2000
• Status: Abandoned Application

• Current Assignee: Silicomp SPA
• Original Assignee: Silicomp SPA
• Inventors: Bolognesi, Gualtiero, Iacopini, Stefano
• Application Number:
  US09/803,163
• Publication Number:
  US 20030007631A1
• Time in Patent Office: Days
• US Class Current: 379/387.02
• CPC Class Codes: F16H 2007/081 Torsion springs
• CPC Class Codes: F16H 2007/0812 Fluid pressure
• CPC Class Codes: F16H 2007/0823 Electric actuators
• CPC Class Codes: F16H 2007/0861 comprising means for sensing tensioner position
• CPC Class Codes: F16H 2007/0893 Circular path
• CPC Class Codes: F16H 7/08 Means for varying tension of belts, ropes, or chains pulleys of adjustable construction F16H55/52 ; gearings with endless belts F16H7/02; tensioning for chains or belts specially adapted for cycles B62M9/16; belt or chain tensioning arrangements for endless conveyors B65G23/44
• CPC Class Codes: G01M 13/023 Power-transmitting endless elements, e.g. belts or chains

Abstract

A control device (4) for connection of a telephone set (2) to at least one speaker (41) for reception of an audio signal and/or of at least one microphone (46) for transmission of an audio signal, comprising a digital signal processor (DSP) (10), an analog-to-digital converter (ADC) (11) to convert the digital signal coming from the telephone set (2) and/or from the microphone (46) to a digital signal that can be processed by the DSP (10), and a digital-to-analog converter (12) to convert the digital signal coming from the DSP (10) to an analog signal to be sent to the telephone set (2) and/or to the speaker (41), the control device (4) performing different functions, such as recognition of the voice conductors, storage and transmission of messages, equalization of the signal received and suppression of ambient noise.

Claims

1. A control device (4) for connection of a telephone set (2) to at least one speaker (41) for reception of an audio signal and/or at least one microphone (46) for transmission of an audio signal, characterized in that it comprises

a digital signal processor (DSP) (10),

an analog-to-digital converter (ADC) (11) to convert the analog signal coming from said telephone set (2) and/or from said microphone (46) to a digital signal that can be processed by the DSP (10) and

a digital-to-analog converter (12) to convert the digital signal coming from said DSP (10) to an analog signal to be sent to said telephone set (2) and/or to said speaker (41).

2. A control device according to claim 1, characterized in that said speaker (41) and said microphone (46) are included in a headset (6).

3. A control device according to claim 1 or 2, characterized in that it provides a man-machine interface comprising a display (8) able to display at least some of the functions of said control device (4) and a keyboard or control panel (9) to allow the user to impart commands to said DSP (10).

4. A control device according to any one of claims 1 to 3. characterized in that it comprises a multiplexer (13, 15) controlled by said DSP (10) for recognition of the sequence of voice conductors (TX(+), TX(−

), RX(+) and RX(−

)), so as to have correct connection of the telephone set (2) to the speaker (41) and to the microphone (46).

5. A control device according to claim 4, characterized in that said multiplexer (13, 15) comprises four inputs (I1, I2, I3, I4) for the four voice conductors coming from said telephone set (2), four outputs (O1, O2, O3, O4) for four voice conductors coming from said microphone (46) and from said speaker (41) and at least two selection lines (S1, S2, S3) coming from said DSP (10).

6. A control device according to any one of the preceding claims, characterized in that it comprises a memory (20) managed by said DSP (10) for storing and sending an audio message.

7. A control device according to claim 6, characterized in that said memory (20) is a flash memory and is addressed by means of a complex programmable logic device (CPLD) (21) that interacts with the DSP (10).

8. A control device according to any one of the preceding claims, characterized in that it comprises an equalization filter (30) for equalization of the audio signal coming from said telephone set (2) and directed toward said speaker (41).

9. A control device according to claim 8, characterized in that said equalization filter (30) is a FIR filter and the equalization curves of said FIR filter are regulated by said DSP (10) by means of commands imparted by the operator by means of the keyboard

10. A control device according to any one of the preceding claims, characterized in that said DSP (10) processes an audio signal comprising the noise coming from the outside environment detected by means of an environmental microphone (42) so as to manage algorithms for suppression of ambient noise both during reception of the signal by means of the speaker (41) and during transmission of the signal by means of the voice microphone (46)

11. A control device according to claim 10, characterized in that said environmental microphone 42 is positioned inside the shell of an earpiece element (40) of the headset (6) facing toward an opening (48) in the shell of the earpiece element, so as to be able to detect noise coming from the outside environment.

12. A control device according to claim 10 or 11, characterized in that it comprises an adder (50, 61) that subtracts from the signal (x(t)) coming from the telephone set (2) a signal (y(t)) indicative of the signal received by said environmental microphone (42) in order to have as the output from said adder (50, 61) a signal (z(t)=x(t)−

y(t)) containing a signal indicative of the ambient noise, which is sent to said speaker (41) to suppress the noise coming from the outside environment.

13. A control device according to claim 12, characterized in that on the path from said environmental microphone (42) to said adder (50) there is a phase shifter (51) to shift the phase of the signal so as to impart a delay and a multiplier (52) to impart an amplification or an attenuation to the signal, said phase shifter (51) and said multiplier (52) being controlled by said DSP (10) through commands imparted by the operator by means of the keyboard (9).

14. A control device according to claim 12, characterized in that on the way from said environmental microphone (42) to said adder (61) an adaptive filter (60) is provided.

15. A control device according to claim 14, characterized in that the coefficients of said adaptive filter (60) are updated by means of a block (62) comprising an algorithm of the NLMS type, implemented by said DSP (10).

16. A control device according to claim 15, characterized in that said block (62) containing the algorithm for updating of the coefficients of the adaptive filter (6) receives a signal coming from an error microphone (43) which detects the signal coming from said speaker (41) and is insulated from the noise of the outside environment and a signal coming from said environmental microphone (42) which is filtered by means of a filter (63) having as its transfer function the spectral estimation of the transfer function (S(z)) of the speaker (41).

17. A control device according to claim 16, characterized in that said error microphone (43) is positioned inside the shell of the earpiece element (40) of the headset (6) in proximity to the speaker (41) and insulated from the outside environment.

18. A control device according to claim 10 or 11, characterized in that it comprises an adder (72) which subtracts from a signal indicative of the signal coming from the voice microphone (46) a signal indicative of the signal received from said environmental microphone (42), in order to have as the output from said adder (72) a signal containing a signal indicative of the ambient noise, which is sent to said telephone apparatus (2) to suppress the noise coming from the outside environment.

19. A control device according to claim 18, characterized in that a first adaptive filter (70) is provided on the path from said voice microphone (46) to said adder (72) and a second adaptive filter (71) is provided on the path from said environmental microphone (42) to said adder (72), the coefficients of said first adaptive filter (70) and said second adaptive filter (71) being updated by a block (73) containing an algorithm for updating of the coefficients of the NLMS type, implemented by said DSP (10), said block (73) containing the algorithm for updating of the coefficients of the filters receiving the output signal from said adder (72).

22. An acoustic headset according to claim 20 or 21, characterized in that it is connected to a telephone set (2) by means of a control device (4) according to any one of claims 1 to 19.

20. A headset comprising at least one earpiece element (40) consisting of a shell that contains a speaker (41) for reception of the audio signal and a voice microphone (46) for transmission of the audio signal, connected by means of a rod (44) to said earpiece element (40), characterized in that it comprises an environmental microphone (42) enclosed inside said shell and facing toward an opening (48) made in said shell and communicating with the outside, so that said environmental microphone (42) can detect noise coming from the outside environment.

21. A headset according to claim 20, characterized in that it comprises an error microphone (43) positioned inside the shell of an earpiece element (40) and insulated from the outside environment, so that said error microphone (43) can detect only the audio signal coming from said speaker (41) provided inside the shell of the earpiece element (40).