1. A method of configuring a transceiver for providing data communications via residential telephone line wiring, the method comprising the steps of:
transmitting a pulse signal having a selected amplitude by a transmit section of the transceiver, receiving the pulse signal by an input circuit in a receiver section of the transceiver to produce a receive signal representing the pulse signal, and
adjusting gain of the input circuit so as to produce the receive signal at a predetermined level.
2. The method of claim 1, wherein the gain of the input circuit is adjusted to a fixed level during initialization of the transceiver.
3. The method of claim 1, wherein the transmitted pulse signal comprises a plurality of access identification pulses preceding data pulses to identify a transmitting network station.
4. The method of claim 3, wherein the gain of the input circuit is adjusted in response to at least one of the access identification pulses.
5. The method of claim 1, wherein the step of adjusting gain comprises comparing amplitude of the receive signal with a preset threshold level.
6. The method of claim 5, wherein the gain is reduced if the amplitude of the receive signal exceeds the threshold level.
7. The method of claim 6, wherein the gain is increased if the amplitude of the receive signal is less that the threshold level.
8. A transceiver for providing data communications over residential telephone line wiring, comprising:
an input circuit for receiving an incoming signal,
an output circuit for transmitting a transmit signal having a selected amplitude, and
a calibration circuit responsive to a receive signal produced by the input circuit in response to the transmit signal for adjusting gain of the input circuit so as to set the receive signal to a predetermined level.
9. The transceiver of claim 8, wherein the input circuit includes an input amplifier for amplifying the incoming signal and an envelope detector for producing an envelope signal representing the incoming signal.
10. The transceiver of claim 9, wherein the calibration circuit is configured for adjusting gain of the input amplifier.
11. The transceiver of claim 8, wherein the transmit signal comprises a plurality of identification pulses for identifying a transmitting station.
12. The transceiver of claim 11, wherein the calibration circuit is configured to adjust the gain of the input circuit, when the input circuit responds to at least one of the identification pulses having the selected amplitude.
13. The transceiver of claim 12, wherein the calibration circuit comprises a comparator arranged at an output of the input circuit for comparing the receive signal produced in response to the at least one of the identification pulses, with a threshold level.
14. The transceiver of claim 13, wherein the calibration circuit further comprises a controller for supplying the input circuit with a gain control value.
15. The transceiver of claim 14, wherein the controller is configured for reducing the gain control value to decrease the gain of the input circuit when the receive signal exceeds the threshold level.
16. The transceiver of claim 15, wherein the controller is configured for increasing the gain control value to raise the gain of the input circuit when the receive signal is less than the threshold level.
17. The transceiver of claim 16, wherein the controller is configured for setting the threshold level.
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 phase varying apparatus for use with an automobile engine including: a camshaft; a drive rotor driven by the crankshaft of the engine; a first and a second control rotor which are rotatable relative to each other and arranged coaxially between the camshaft and drive rotor; first and second torque means for respectively providing the first and second control rotor with a torque for causing a rotation relative to the drive rotor; and a phase angle varying mechanism for varying the phase angle of the camshaft relative to the drive rotor in response to the rotation of the first or second control rotor relative to the drive rotor, the phase varying apparatus characterized in that the phase angle varying mechanism comprises:
a circular eccentric cam integral with the camshaft;
a first link in the form of a substantial cylinder which is supported by the circular eccentric cam for rotation about the cam center of the circular eccentric cam;
a second link in the form of a substantial cylinder which is rotatably supported by the first link for eccentric rotation about the first axis of the first link and supported by the first control rotor for rotation about a second axis of the second link that is offset from the rotational axis of the camshaft;
a quasi-radial guide mechanism for keeping movable the first or second link in the quasi-radial direction of the respective rotor; and
displacement forcing means for applying a force on, and displacing, either one of the first link and second links in the quasi-radial guide mechanism in the quasi-radial direction.
2. The phase varying apparatus according to claim 1, wherein
the quasi-radial guide mechanism is a first link guide groove formed in the drive rotor to extend in a quasi-radial direction, for guiding the first link in the quasi-radial direction; and
the drive rotor has a cylindrical portion for supporting the outer periphery of the first control rotor.
3. The phase varying apparatus according to claim 2, wherein
a bush having a circular hole and parallel cutaway portions on the opposite sides thereof is provided between the first link and the first link guide groove;
the first link is slidably inscribed in the circular hole of the bush without touching the first link guide groove; and
the cutaway portions formed on the opposite sides of the bushes are guided by the first link guide groove so that the bush is displaced along the first link guide groove together with the first link.
4. The phase varying apparatus according to claim 2, wherein the first link guide groove is inclined with respect to a radial direction of the drive rotor.
5. The phase varying apparatus according to claim 1, wherein
the quasi-radial guide mechanism comprises:
slide member protruding from the second link; and
a slide member guide groove in the form of a groove formed in the drive rotor to extend in a quasi-radial direction for holding the slide member movably in the quasi-radial direction;
the positions of the center axes of the first link, second link, and of the slide member with respect to the rotational axis of the center shaft are aligned with substantially the same line; and
the first control rotor has a circular eccentric hole for rotatably inscribing therein the second link.
6. The phase varying apparatus according to claim 3, wherein the first link guide groove is inclined with respect to a radial direction of the drive rotor.