1. A demodulation device comprising:
a first power control circuit for keeping the amplitude of a modulated input signal constant for slow fluctuations in the amplitude of the carrier;
a plurality of demodulation circuits coupled in series on the output side of the first power control circuit, the demodulation circuits receiving the modulated input signal and applying a demodulation processing to the input signal;
a second power control circuit generating a control signal having at least two states that include a signal present state representing detection of the presence of the input signal and a signal disappeared state representing detection of the disappearance of the input signal; and
means for deactivating the demodulation circuits when the control signal changes from the signal present state to the signal disappeared state so as to prevent the demodulation circuits from becoming desynchronized, and for activating the demodulation circuits when the control signal changes from the signal disappeared state to the signal present state so as to enable a fast restart of the demodulation processing.
2. The demodulation device according to claim 1,
wherein the demodulation circuits are clocked by a synchronization signal having a first state in which the demodulation circuits are active and a second state in which the demodulation circuits are inactive, and
the means for deactivating and activating forces the synchronization signal into the second state when the control signal is in the signal disappeared state, and maintains the synchronization signal in the first state when the control signal is in the signal present state.
3. The demodulation device according to claim 2, wherein the means for deactivating and activating includes an AND logic circuit having one input that receives the control signal from the second power control circuit, another input that receives the synchronization signal, and an output coupled to each of the demodulation circuits.
4. The demodulation device according to claim 2, wherein the first state of the synchronization signal corresponds to a clock signal and the second state of the synchronization signal corresponds to a low logical state.
5. The demodulation device according to claim 1,
wherein the second power control circuit includes a power estimating circuit that estimates the power of the input signal, and a state machine having at least two states controlled by a double threshold detection with hysteresis, and
the state machine generates the control signal in the signal present state when the estimated power exceeds a first threshold, and generates the control signal in the signal disappeared state when the estimated power is lower than a second threshold.
6. The demodulation device according to claim 5, further comprising:
means for memorizing demodulation parameters of the input signal whenever the input signal is detected as being present during at least two successive power estimates; and
means for configuring the demodulation circuits as a function of the memorized parameters when the control signal changes from the signal disappeared state to the signal present state.
7. The demodulation device according to claim 1, wherein the demodulation circuits comprise two synchronization loops and an equalizing circuit.
8. The demodulation device according to claim 7, wherein the demodulation circuits further comprise an error correction circuit without a return channel.
9. The demodulation device according to claim 1, wherein the input signal is an amplitude and phase modulated signal using the QAM modulation technique that is transmitted through a cabled network.
10. A system for receiving a modulated signal, said system comprising:
a channel selector device for transposing the modulated signal; and
a demodulation device coupled to the channel selector device, the demodulation device including:
a first power control circuit for keeping the amplitude of a modulated input signal constant for slow fluctuations in the amplitude of the carrier;
a plurality of demodulation circuits coupled in series on the output side of the first power control circuit, the demodulation circuits receiving the modulated input signal and applying a demodulation processing to the input signal;
a second power control circuit generating a control signal having at least two states that include a signal present state representing detection of the presence of the input signal and a signal disappeared state representing detection of the disappearance of the input signal; and
means for deactivating the demodulation circuits when the control signal changes from the signal present state to the signal disappeared state so as to prevent the demodulation circuits from becoming desynchronized, and for activating the demodulation circuits when the control signal changes from the signal disappeared state to the signal present state so as to enable a fast restart of the demodulation processing.
11. The system according to claim 10,
wherein the demodulation circuits of the demodulation device are clocked by a synchronization signal having a first state in which the demodulation circuits are active and a second state in which the demodulation circuits are inactive, and
the means for deactivating and activating of the demodulation device forces the synchronization signal into the second state when the control signal is in the signal disappeared state, and maintains the synchronization signal in the first state when the control signal is in the signal present state.
12. The system according to claim 10,
wherein the second power control circuit of the demodulation device includes a power estimating circuit that estimates the power of the input signal, and a state machine having at least two states controlled by a double threshold detection with hysteresis, and
the state machine generates the control signal in the signal present state when the estimated power exceeds a first threshold, and generates the control signal in the signal disappeared state when the estimated power is lower than a second threshold.
13. The system according to claim 12, wherein the demodulation device further comprises:
means for memorizing demodulation parameters of the input signal whenever the input signal is detected as being present during at least two successive power estimates; and
means for configuring the demodulation circuits as a function of the memorized parameters when the control signal changes from the signal disappeared state to the signal present state.
14. The system according to claim 10, wherein the demodulation circuits of the demodulation device comprise two synchronization loops and an equalizing circuit.
15. The system according to claim 14, wherein the demodulation circuits of the demodulation device further comprise an error correction circuit without a return channel.
16. A method for demodulating a modulated input signal, said method comprising the steps of:
keeping the amplitude of a modulated input signal constant for slow fluctuations in the amplitude of the carrier;
selectively applying a demodulation processing to the input signal;
generating a control signal having at least two states that include a signal present state representing detection of the presence of the input signal and a signal disappeared state representing detection of the disappearance of the input signal;
deactivating application of the demodulation processing when the control signal changes from the signal present state to the signal disappeared state so as to prevent desynchronization of the demodulation processing; and
activating application of the demodulation processing when the control signal changes from the signal disappeared state to the signal present state so as to enable a fast restart of the demodulation processing.
17. The method according to claim 16, further comprising the step of:
clocking the demodulation processing by a synchronization signal having a first state in which the demodulation processing is activated and a second state in which the demodulation processing is deactivated,
wherein the deactivating step comprises forcing the synchronization signal into the second state, and
the activating step comprises forcing the synchronization signal into the first state.
18. The method according to claim 16, further comprising the steps of:
selectively memorizing demodulation parameters of the input signal; and
configuring the demodulation processing as a function of the memorized parameters when the control signal changes from the signal disappeared state to the signal present state.
19. The method according to claim 16, wherein the demodulation processing comprises correcting errors between data sending and reception frequencies, correcting errors between data modulation and demodulation frequencies, and correcting linearity defects.
20. The method according to claim 19, wherein the demodulation processing further comprises correcting errors and eliminating redundancy.
The claims below are in addition to those above.
All refrences to claim(s) which appear below refer to the numbering after this setence.
1. A utility knife, comprising:
a handle;
a blade holder connected to the handle by means that is movable about at least two axes for connecting the blade holder to the handle for movement in a single curvilinear path relative to the handle between a retracted position and an extended position;
a button assembly that is moveable along a transverse linear path with respect to the handle and that cooperates with the blade holder to move the blade holder to the extended position; and
a utility blade replaceably attached to the blade holder for selective removal and replacement of the utility blade.
2. The utility knife of claim 1, wherein the handle further comprises a first aperture from which the blade holder projects in the extended position.
3. The utility knife of claim 2, wherein the handle further comprises a second aperture from which the blade holder projects as it is moved between the retracted position and the extended position.
4. A utility knife, comprising:
a handle including a right side, a left side, a front face, and a top side, and a first aperture and a second aperture;
a blade holder connected to the handle by means that is movable about at least two axes for connecting the blade holder to the handle for movement in a curvilinear path relative to the handle between a retracted position and an extended position;
a utility blade replaceably attached to the blade holder for selective removal and replacement of the utility blade, wherein the first aperture is in the front face from which the blade holder projects in the extended position and the second aperture is in the top side from which the blade holder projects as it is moved between the retracted position and the extended position.
5. The utility knife of claim 4, wherein the blade holder further comprises a slot having a vertical portion perpendicular to a horizontal portion, which cooperate to provide the blade holder with ability to move in the curvilinear path with respect to the handle.
6. The utility knife of claim 5, the utility knife further comprises a button assembly that cooperates with the slot in the blade holder, wherein the button assembly pushes the blade holder to the extended position and the blade holder moves with respect to the button assembly.
7. A utility knife, comprising:
a handle;
a blade holder connected to the handle by means that is movable about at least two axes for connecting the blade holder to the handle for movement in a curvilinear path relative to the handle between a retracted position and an extended position with a top surface of the blade holder maintaining a substantially consistent perpendicular orientation with respect to a right side of the handle; and
a utility blade replaceably attached to the blade holder for selective removal and replacement of the utility blade.
8. The utility knife of claim 7, wherein the handle further comprises a first aperture from which the blade holder projects in the extended position, a second aperture from which the blade holder projects as it is moved between the retracted position and the extended position, the right side, a left side, a front face, and a top side, wherein the first aperture is in the front face and the second aperture is in the top side.
9. The utility knife of claim 8, wherein the blade holder further comprises a slot having a vertical portion perpendicular to a horizontal portion, which cooperate to provide the blade holder with ability to move in the curvilinear path with respect to the handle.
10. The utility knife of claim 9, and further comprising a button assembly that cooperates with the slot in the blade holder, wherein the button assembly pushes the blade holder to the extended position and the blade holder moves with respect to the button assembly.
11. The utility knife of claim 7, and further comprising at least two axes about which the blade holder is pivotally attached to the handle.