What is claimed is:
1. A method for operating a modem on a communication channel the method comprising the steps of:
receiving a continuous analog signal transmitted on the communication channel with a receiver circuit of the modem, the analog signal comprising packet information and idle information;
detecting the presence of the idle information with the receiver circuit; and
entering a standby mode within the receiver circuit upon detecting the presence of the idle information, wherein an amount of processing performed by the receiver circuit is reduced during the standby mode.
2. The method of claim 1, further comprising the step of disabling selected circuitry within the receiver circuit when the receiver circuit is in the standby mode.
3. The method of claim 2, wherein the receiver circuit comprises a symbol decision circuit, a channel decoder and a framer, the method further comprising the step of disabling the symbol decision circuit, the channel decoder and the framer when the receiver circuit is in the standby mode.
4. The method of claim 1, further comprising the step of reducing the amount of processing performed by selected circuitry within the receiver circuit when the receiver circuit is in the standby mode.
5. The method of claim 4, wherein the receiver circuit comprises an echo canceler, the method further comprising the step of reducing a length of the echo canceler when the receiver circuit is in the standby mode.
6. The method of claim 4, wherein the receiver circuit comprises an equalizer, the method further comprising the step of reducing the processing requirements of the equalizer when the receiver circuit is in the standby mode.
7. The method of claim 1, wherein the step of detecting further comprises the steps of:
fully demodulating the analog signal with the receiver circuit to provide a digital bit stream; and
determining whether the digital bit stream corresponds with a predetermined idle bit stream.
8. The method of claim 7, wherein the step of entering the standby mode further comprises the step of entering the standby mode if the digital bit stream corresponds with the predetermined idle bit stream.
9. The method of claim 8, further comprising the steps of:
generating an idle bit pattern if the digital bit stream corresponds with the predetermined idle bit stream;
converting the idle bit pattern to a plurality of expected idle symbols;
comparing the expected idle symbols with a plurality of soft symbols which are generated by the receiver circuit at a reduced processing power in response to the analog signal; and
remaining in the standby mode as long as the expected idle symbols match the soft symbols.
10. The method of claim 9, further comprising the step of exiting the standby mode when an expected idle symbol does not match a corresponding soft symbol.
11. The method of claim 10, further comprising the steps of:
storing a most recent history of the analog signal in a buffer; and
accessing the buffer after the step of exiting the standby mode, thereby enabling the receiver circuit to process the most recent history of the analog signal.
12. The method of claim 8, further comprising the steps of:
generating an idle bit pattern if the digital bit stream corresponds with the predetermined idle bit stream;
converting the idle bit pattern to a plurality of expected differences between successive idle symbols;
comparing the expected differences with a plurality of actual differences between successive idle symbols which are generated by the receiver circuit at a reduced processing power in response to the analog signal; and
remaining in the standby mode as long as the expected differences correspond with the actual differences.
13. The method of claim 8, further comprising the steps of:
accessing a memory which stores a repetitive pattern of expected idle symbols if the digital bit stream corresponds with the predetermined idle bit stream;
comparing the expected idle symbols with a plurality of soft symbols which are generated by the receiver circuit at a reduced processing power in response to the analog signal; and
remaining in the standby mode as long as the expected idle symbols match the soft symbols.
14. The method of claim 1, wherein the analog signal comprises a multi-carrier signal having a plurality of sub-carrier signals, wherein the step of detecting further comprises the steps of:
selectively demodulating one or more of the sub carrier signals with the receiver circuit to provide a digital bit stream; and
determining whether the digital bit stream corresponds with a predetermined idle bit stream.
15. The method of claim 1, further comprising the steps of:
monitoring the quality of the analog signal on the communication channel by the receiver circuit; and
reducing the amount of processing performed by the receiver circuit if the quality exceeds a predetermined standard.
16. The method of claim 1, further comprising the steps of:
determining a symbol rate and signal constellation associated with the analog signal; and
adjusting the amount of processing performed by the receiver circuit to a predetermined quality level associated with the determined symbol rate and signal constellation.
17. A receiver circuit for use in a modem, the receiver circuit comprising:
means for receiving a continuous analog signal which comprises packet information and idle information;
means for detecting the presence of the idle information; and
means for entering a standby mode within the receiver circuit upon detecting the presence of the idle information,-wherein an amount of processing performed by the receiver circuit is reduced during the standby mode.
18. A receiver circuit for use in a modem, the receiver circuit comprising:
an analog to digital (AD) converter for receiving an analog signal which comprises packet information and idle information;
a carrier recovery circuit coupled to the AD converter, wherein the carrier recovery circuit provides soft symbol decisions regarding the identity of the packet information and idle information;
a symbol decision circuit coupled to the carrier recovery circuit, wherein the symbol decision circuit provides hard symbol decisions regarding the identity of the packet information and idle information; and
an idle detector circuit coupled to the symbol decision circuit, wherein the idle detector circuit detects the presence of idle information in response to the hard symbol decisions provided by the symbol decision circuit, and wherein the idle detector circuit instructs the receiver circuit to enter a reduced processing mode upon detecting the presence of idle information.
19. The receiver circuit of claim 18, further comprising:
an idle generator circuit coupled to the idle detector circuit, wherein the idle generator circuit generates an idle bit pattern when the idle detector detects the presence of idle information;
an idle symbol predictor coupled to the idle generator circuit, wherein the idle symbol predictor provides a plurality of expected idle symbols in response to the idle bit pattern; and
a comparator coupled to the idle symbol predictor and the carrier recovery circuit, wherein the comparator compares the expected idle symbols with the soft symbol decisions, wherein the comparator causes the receiver circuit to remain in the standby mode as long as the expected idle symbols match the soft symbol decisions and wherein the comparator causes the receiver circuit to exit the standby mode when an expected idle symbol does not match the soft symbol decision.
20. The receiver circuit of claim 18, further comprising a buffer coupled to the AD converter, wherein the buffer stores a most recent history of the analog signal.
21. A receiver circuit for use in a modem, the receiver circuit comprising:
an analog to digital (AD) converter for receiving an analog signal which comprises packet information and idle information;
an equalizer circuit coupled to the AD converter, wherein the equalizer circuit provides actual equalized digital samples which correspond to the identity of the packet information and idle information;
a symbol decision circuit coupled to the equalizer circuit, wherein the symbol decision circuit provides hard symbol decisions regarding the identity of the packet information and idle information; and
an idle detector circuit coupled to the symbol decision circuit, wherein the idle detector circuit detects the presence of idle information in response to the hard symbol decisions provided by the symbol decision circuit, and wherein the idle detector circuit instructs the receiver circuit to enter a reduced processing mode upon detecting the presence of idle information.
22. The receiver circuit of claim 21, further comprising:
an idle generator circuit coupled to the idle detector circuit, wherein the idle generator circuit generates an idle bit pattern when the idle detector detects the presence of idle information;
an idle symbol predictor coupled to the idle generator circuit, wherein the idle symbol predictor provides a plurality of expected equalized digital samples associated with expected idle symbols in response to the idle bit pattern; and
a comparator coupled to the idle symbol predictor and the equalizer circuit, wherein the comparator compares the expected equalized digital samples with the actual equalized digital samples, wherein the comparator causes the receiver circuit to remain in the standby mode as long as the expected equalized digital samples match the actual equalized digital samples, and wherein the comparator causes the receiver circuit to exit the standby mode when an expected equalized digital sample does not match an actual equalized digital sample.
23. A method for operating a modem on a telephone line, the method comprising the steps of:
modulating packets of digital information by a transmitter circuit of the modem, wherein the packets of digital information are converted into analog signal bursts of discrete duration;
transmitting the analog signal bursts from the transmitter circuit to the telephone line; and
providing no signal from the transmitter circuit to the telephone line between the analog signal bursts.
24. The method of claim 23, wherein the step of modulating comprises performing quadrature amplitude modulation (QAM) on the packets of digital information.
25. The method of claim 23, wherein the step of modulating comprises performing carrier-less amplitude and phase modulation (CAP) on the packets of digital information.
26. The method of claim 23, wherein the step of modulating comprises performing multi-carrier modulation with respect to the packets of digital information.
27. The method of claim 23, wherein the telephone line comprises an unshielded twisted pair.
28. The method of claim 23, further comprising the step of transmitting an analog non-idle state signal by the transmitter circuit, wherein the non-idle state signal is appended to the beginning of the analog signal bursts.
29. The method of claim 28, wherein the non-idle state signal is a pure tone signal.
30. The method of claim 28, wherein the non-idle state signal is a sub-carrier signal within a discrete multi-carrier signalling scheme.
31. The method of claim 23, further comprising the steps of:
monitoring the telephone line with a receiver circuit of the modem;
detecting the presence and absence of the analog signal bursts on the telephone line by a non-idle detector of the receiver circuit;
demodulating the analog signal bursts with the receiver circuit when the non-idle detector detects the presence of the analog signal bursts on the telephone line; and
disabling the demodulating within the receiver circuit when the non-idle detector detects the absence of the analog signal bursts on the telephone line.
32. The method of claim 31, wherein the step of detecting comprises the step of monitoring the telephone line for the presence and absence of energy.
33. The method of claim 31, further comprising the step of transmitting an analog non-idle state signal by the transmitter circuit prior to each of the analog signal bursts, wherein the step of detecting comprises the step of monitoring the telephone line for the non-idle state signal.
34. The method of claim 31, further comprising the step of disabling an echo canceler within the receiver circuit in the absence of local transmit data.
35. The method of claim 31, further comprising the steps of:
monitoring the quality of the analog signal bursts on the telephone line by the receiver circuit; and
reducing the amount of processing performed by the receiver circuit during the demodulation step if the quality exceeds a predetermined standard.
36. The method of claim 23, further comprising the steps of:
monitoring the telephone line during predetermined discrete time intervals with a receiver circuit of the modem; and
detecting the presence and absence of the analog signal burst on the telephone line by a non-idle detector of the receiver circuit during the discrete time intervals.
37. The method of claim 23, further comprising the steps of:
monitoring the telephone line with a receiver circuit of the modem;
decoding the analog signal bursts with the receiver circuit to determine modulation parameters associated with the analog signal bursts; and
adjusting the level of processing performed by the receiver circuit to a predetermined level associated with the determined modulation parameters.
38. The method of claim 37, wherein the modulation parameters comprise a symbol rate and a signal constellation.
39. The method of claim 37, wherein the modulation parameters comprise an error correction scheme.
40. A modem system for transmitting information on a telephone line, the modem system comprising:
means for modulating packets of digital information by a transmitter circuit of the modem, wherein the packets of digital information are converted into analog signal bursts of discrete duration;
means for transmitting the analog signal bursts from the transmitter circuit to the telephone line; and
means for providing no signal from the transmitter circuit to the telephone line between the analog signal bursts.
41. The modem system of claim 40, further comprising:
means for monitoring the telephone line with a receiver circuit of the modem;
means for detecting the presence and absence of the analog signal bursts on the telephone line by a non-idle detector of the receiver circuit;
means for demodulating the analog signal bursts with the receiver circuit when the non-idle detector detects the presence of the analog signal bursts on the telephone line; and
means for disabling the demodulating within the receiver circuit when the non-idle detector detects the absence of the analog signal bursts on the telephone line.
42. A method for transferring information on a telephone line, the method comprising the steps of:
modulating packets of digital information by a first transmitter circuit, wherein the packets of digital information are converted into first analog signal bursts of discrete duration, and wherein the first transmitter circuit is coupled to a first telephone line;
providing no signal from the first transmitter circuit to the first telephone line between the first analog signal bursts;
modulating packets of digital information by a second transmitter circuit, wherein the packets of digital information are converted into second analog signal bursts of discrete duration, and wherein the second transmitter circuit is coupled to a second telephone line;
providing no signal from the second transmitter circuit to the second telephone line between the second analog signal bursts;
monitoring the first and second telephone lines with a multi-line network access circuit;
detecting the presence and absence of the first and second analog signal bursts on the telephone line by a non-idle detector of multi-line network access circuit;
demodulating the first and second analog signal bursts with a single receiver circuit of the multi-line network access circuit when the non-idle detector detects the presence of the first and second analog signal bursts on the telephone line; and
disabling the demodulating within the receiver circuit when the non-idle detector detects the absence of the first and second analog signal bursts on the telephone line.
43. The method of claim 42, further comprising the step of buffering the first and second analog signal bursts within the multi-line network access circuit.
44. The method of claim 42, further comprising the steps of:
selecting a first set of operating coefficients within the receiver circuit to process the first set of analog signal bursts; and
selecting a second set of operating coefficients within the receiver circuit to process the second set of analog signal bursts.
45. A modem system comprising:
a plurality of analog to digital (AD) converters coupled to a corresponding plurality of telephone lines;
a non-idle detector circuit coupled to each of the AD converters, wherein the non-idle detector identifies a first set of telephone lines which are carrying packet information and a second set of telephone lines which are not carrying packet information; and
a scheduling circuit coupled to the non-idle detector circuit, wherein the scheduling circuit couples the AD converters associated with the first set of telephone lines to one or more digital signal processing resources, wherein a plurality of the telephone lines are operably coupled to a single digital signal processing resource.
46. The modem system of claim 45, further comprising a buffer coupled to each of the AD converters.
47. A method for operating a plurality of modems on a single telephone line, the method comprising the steps of:
modulating packets of digital information by the modems, wherein the packets of digital information are converted into analog signal bursts of discrete duration;
transmitting the analog signal bursts from the modems to the telephone line;
providing no signal from the modems to the telephone line between the analog signal bursts; and
arbitrating the transmitting of the analog signal bursts from the modems to the telephone line such that only one modem is transmitting analog signal bursts to the telephone line at any given time.
48. The method of claim 47, further comprising the steps of:
monitoring the telephone line with the modems;
detecting the presence and absence of the analog signal bursts on the telephone line by nonidle detectors within the modems;
demodulating the analog signal bursts with the modems when the non-idle detectors detect the presence of the analog signal bursts on the telephone line; and
disabling the demodulating within the modems when the non-idle detectors detect the absence of the analog signal bursts on the telephone line.
49. The method of claim 47, further comprising the step of locating a plurality of the modems at a subscriber’s residence.
50. The method of claim 47, further comprising the step of locating one of the modems at a telephone company central office.
51. The method of claim 47, further comprising the step of locating one of the modems at a telephone company remote terminal.
52. The method of claim 47, wherein the step of arbitrating is performed in accordance with a contention based protocol.
53. The method of claim 47, wherein the step of arbitrating is performed using a reservation based protocol.
54. The method of claim 47, wherein the step of arbitrating is performed in accordance with a frequency division multiple access (FDMA) protocol.
55. The method of claim 47, wherein the step of arbitrating is performed in accordance with a code division multiple access (CDMA) protocol.
56. The method of claim 47, wherein the step of arbitrating is performed in accordance with a time division multiple access (TDMA) protocol.
57. The method of claim 47, wherein each of the analog signal bursts comprises a preamble and a corresponding main body, the method further comprising the steps of:
transmitting each preamble in accordance with a predetermined first modulation protocol; and
transmitting a first main body associated with a first preamble in accordance with a second modulation protocol.
58. The method of claim 57, wherein the second modulation protocol has a data rate which is greater than a data rate associated with the first modulation protocol and wherein the second modulation protocol is identified by the first preamble.
59. The method of claim 57, wherein the first preamble identifies a level of error control for the second modulation protocol.
60. The method of claim 57, wherein the first preamble identifies a version or type of the first preamble.
61. The method of claim 57, wherein the first preamble identifies source addresses associated with the analog signal bursts.
62. The method of claim 57, wherein the first preamble identifies destination addresses associated with the analog signal bursts.
63. The method of claim 57, wherein the first preamble identifies line codes associated with the analog signal bursts.
64. The method of claim 57, wherein the first preamble identifies packet lengths associated with the is analog signal bursts.
65. The method of claim 57, wherein the first preamble identifies expected time intervals between successive analog signal bursts.
66. The method of claim 57, further comprising the step of:
transmitting a second main body associated with a second preamble in accordance with a third modulation protocol.
67. The method of claim 66, wherein the third modulation protocol is different from the second modulation protocol.
68. A modem system having a plurality of modems operably connected to a single telephone line, the modem system comprising:
means for modulating packets of digital information by the modems, wherein the packets of digital information are converted into analog signal bursts of discrete duration;
means for transmitting the analog signal bursts from the modems to the telephone line;
means for providing no signal from the modems to the telephone line between the analog signal bursts; and
means for arbitrating the transmitting of the analog signal bursts from the modems to the telephone line such that only one modem is transmitting analog signal bursts to the telephone line at any given time.
69. A method of implementing a multi-line network access circuit, the method comprising the steps of:
transmitting a plurality of digital data packets from a plurality of sources to a multi-line network circuit, wherein the digital data packets do not include idle information;
identifying destination addresses associated with the digital data packets using an address monitor within the multi-line network access circuit;
multiplexing digital data packets from different sources to a common digital signal processing resource;
modulating digital data packets from different sources with the common digital signal processing resource; and
de-multiplexing the modulated digital data packets from the common digital signal processing resource onto telephone lines which are associated with the destination addresses.
70. The method of claim 69, further comprising the step of generating idle information for each of the telephone lines using a common idle generator.
71. The method of claim 69, wherein the common idle generator generates the idle information by accessing a memory which stores the idle information.
72. The method of claim 69, further comprising the step of generating non-idle state signalling for each of the telephone lines using a non-idle state signal generator.
73. A method of implementing a multi-cast network is access circuit, the method comprising the steps of:
transmitting a digital data packet from a source to the multi-cast network access circuit, wherein the digital data packet does not include idle information;
identifying a plurality of destination addresses associated with the digital data packet;
routing the digital data packet to a digital signal processing resource;
modulating the digital data packet with the digital signal processing resource; and
de-multiplexing the modulated digital data packet from the common digital signal processing resource to a plurality of telephone lines associated with the destination addresses.
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 programmable microcomputer controlled load sensing system for a log washer apparatus for washing off aggregate material, comprising:
a log washer tank having a pivotally mounted lower end and having an upper end;
a pair of hydraulic cylinders, each hydraulic cylinder having a cylinder base depending from the upper end of the log washer tank and a piston rod attached to a fixed ground support, said hydraulic cylinders disposed on opposite width sides of the log washer tank;
a combinerdivider valve connected to said pair of hydraulic cylinders;
a hydraulic pump and a hydraulic fluid reservoir connected to the combinerdivider valve for pumping hydraulic fluid to and receiving said fluid from said combinerdivider valve for extending and retracting the piston rods;
an electronic pressure sensor disposed between said hydraulic pump and said combinerdivider valve, the sensor having a first state when hydraulic pressure exceeds a high pressure limit, a second state when hydraulic pressure falls below a low pressure limit, and a third state when hydraulic pressure is between the high pressure and low pressure limits as detected by a programmable microcomputer;
raising means for extending the piston rods of the pair of hydraulic cylinders when hydraulic pressure falls below the low pressure limit as detected and controlled by the programmable microcomputer; and
lowering means for retracting the piston rods of the pair of hydraulic cylinders when hydraulic pressure is above the high pressure limit as detected and controlled by the programmable microcomputer;
whereby the log washer tank is raised and lowered to an angle of incline with only the aggregate material load by the programmable microcomputer to promote efficient washing in response to changes in weight of each load.
2. The programmable microcomputer controlled load sensing system according to claim 1, further comprising a check valve disposed between said hydraulic pump and said combinerdivider valve for preventing back flow of hydraulic fluid through said hydraulic pump.
3. The programmable microcomputer controlled load sensing system according to claim 1, further comprising a high pressure relief valve disposed between said hydraulic pump and said combinerdivider valve for diverting hydraulic fluid to said hydraulic reservoir when hydraulic pressure produced by said hydraulic pump exceeds a high pressure limit as controlled by the programmable microcomputer.
4. The programmable microcomputer controlled load sensing system according to claim 1, wherein said raising means comprises a hydraulic valve disposed between said hydraulic pump and said combinerdivider valve, the hydraulic valve having a solenoid connected to said highlow pressure sensor for opening and closing the hydraulic valve.
5. The programmable microcomputer controlled load sensing system according to claim 1, wherein said lowering means comprises a hydraulic valve disposed between said hydraulic reservoir and said combinerdivider valve, the hydraulic valve having a solenoid connected to said highlow pressure sensor for opening and closing the hydraulic valve.
6. The programmable microcomputer controlled load sensing system according to claim 1, further comprising a needle valve disposed between said combinerdivider valve and said hydraulic reservoir for regulating the flow rate of hydraulic fluid to said hydraulic reservoir.