US5394437A — High-speed modem synchronized to a remote CODEC

Claim 1

Independent Claim 160 words

Apparatus comprising: first means for developing a clock signal of period T seconds; and second means, responsive to the first means, for developing an output signal of the apparatus, which output signal is band-limited to frequencies below f c and contains information-bearing analog pulses, at least some of which are spaced T seconds apart; wherein T is less than 1/2 f c , wherein each of the information-bearing analog pulses represents a magnitude that corresponds to an applied symbol from a constellation of symbols, wherein in each set of M consecutive clock periods T there is a grouping of N of said analog samples, where M and N are integers and N is less than M, and wherein said second means comprises N analog pulse generation means with their outputs combined, and each one of the analog samples in the grouping of N of said analog samples is generated by a different one of the N analog pulse generation means.

Claim 2

Dependent Claim 160 words

Apparatus comprising: first means for developing a clock signal of period T seconds; and second means, responsive to the first means, for developing an output signal of the apparatus, which output signal is band-limited to frequencies below f c and contains information-bearing analog pulses, at least some of which are spaced T seconds apart; wherein T is less than 1/2 f c , wherein each of the information-bearing analog pulses represents a magnitude that corresponds to an applied symbol from a constellation of symbols, wherein in each set of M consecutive clock periods T there is a grouping of N of said analog samples, where M and N are integers and N is less than M, and wherein said second means comprises N analog pulse generation means with their outputs combined, and each one of the analog samples in the grouping of N of said analog samples is generated by a different one of the N analog pulse generation means.

Claim 3

Dependent Claim 18 words

The apparatus of claim 1 wherein at least one of the analog pulse generation means is a filter.

Claim 4

Dependent Claim 99 words

The apparatus of claim 1 wherein said second means comprises N analog pulse generation means, responsive to applied symbols, that contribute to the output signal of the apparatus, and switch means for applying symbols to the N analog pulse generation means to cause each one of the analog samples in the grouping of N of said analog samples to be generated by a different one of the analog pulse generation means, resulting thereby in each one of the analog pulse generation means to be associated with a particular clock period in the set of M consecutive clock periods T.

Claim 5

Dependent Claim 25 words

The apparatus of claim 3 wherein the symbols are applied to the second means at intervals mT, where m is an integer greater than 0.

Claim 6

Dependent Claim 35 words

The apparatus of claim 3 further comprising a buffer for receiving symbols at rate 2 f c and outputting symbols to the second means at intervals mT, where m is an integer greater than 0.

Claim 7

Dependent Claim 44 words

The apparatus of claim 3 wherein each of the analog pulse generation means is characterized by a transfer function that develops essentially no output when the other of the N analog samples develop a peak output out of their respective analog pulse generation means.

Claim 8

Dependent Claim 79 words

The apparatus of claim 3 wherein each of the analog pulse generation means is characterized by a transfer function ##EQU8## where p is an index integer, K p is a constant (and there are p such constants), t p is the p th sampling interval, T s is the sampling period, t q is the q th sampling interval where q is another integer index ranging from one to seven, and y p is the p th signal sample.

Claim 9

Dependent Claim 50 words

The apparatus of claim 1, wherein the first means further comprising control means responsive to signals from a remote system to develop said clock signal, which control means includes delay means for changing the phase of the developed clock in response to a training signal applied to said remote system.

Claim 10

Dependent Claim 18 words

The apparatus claim 8 wherein said control means affects magnitudes of the symbols applied to the second means.

Claim 11

Dependent Claim 20 words

The apparatus claim 8 wherein said control means affects magnitudes of the information-bearing analog pulses developed by the second means.

Claim 12

Dependent Claim 65 words

Apparatus comprising: an D/A converter operating under control of a first clock, for communicating signals to a A/D converter having a second clock, control means for receiving information from the A/D converter, means, responsive to said control means, for synchronizing the first clock to the second clock, and means, responsive to said control means, for adjusting levels of the output signal of the D/A converter.

Claim 13

Dependent Claim 65 words

Apparatus comprising: an D/A converter operating under control of a first clock, for communicating signals to a A/D converter having a second clock, control means for receiving information from the A/D converter, means, responsive to said control means, for synchronizing the first clock to the second clock, and means, responsive to said control means, for adjusting levels of the output signal of the D/A converter.

Claim 14

Dependent Claim 67 words

Apparatus comprising: an A/D converter operating under control of a first clock, for receiving signals from a D/A converter having a second clock, control means for deriving information from the signal received by the A/D converter, means, responsive to said control means, for synchronizing the first clock to the second clock, and means, responsive to said control means, for adjusting the slicing levels of the A/D converter.

Claim 15

Dependent Claim 67 words

Apparatus comprising: an A/D converter operating under control of a first clock, for receiving signals from a D/A converter having a second clock, control means for deriving information from the signal received by the A/D converter, means, responsive to said control means, for synchronizing the first clock to the second clock, and means, responsive to said control means, for adjusting the slicing levels of the A/D converter.

Claim 16

Dependent Claim 73 words

An arrangement for communicating digital information comprising a digital-to-analog conversion means, a analog-to-digital conversion means operating with a clock, and an analog medium coupling the output of the digital-to-analog conversion means with the input of the analog-to-digital conversion means, CHARACTERIZED IN THAT: the digital-to-analog conversion means develops an analog output in synchronism with said clock at levels that are cognizant of slicing levels of the analog-to-digital conversion means, and of said analog medium.

Claim 17

Dependent Claim 73 words

An arrangement for communicating digital information comprising a digital-to-analog conversion means, a analog-to-digital conversion means operating with a clock, and an analog medium coupling the output of the digital-to-analog conversion means with the input of the analog-to-digital conversion means, CHARACTERIZED IN THAT: the digital-to-analog conversion means develops an analog output in synchronism with said clock at levels that are cognizant of slicing levels of the analog-to-digital conversion means, and of said analog medium.

Claim 18

Dependent Claim 43 words

The arrangement of claim 13 said analog output is of such a magnitude that when the analog output signal is communicated to the analog-to-digital conversion means, the analog-to-digital conversion means develops a digital output that is the same as the applied digital signal.

Claim 19

Dependent Claim 169 words

An modem including a transmitting section for developing an analog signal in response to an applied digital stream, which analog signal is destined to a remote clocked conversion means, a receiving section for developing a digital string in response to an analog signal from the remote clocked conversion means, means for developing a clock in synchronism with the clock in the remote conversion means, and means for employing the developed clock in the transmitting section, the receiving section comprising: a switched filter, a transmission-medium-emulating filter responsive the output of the switched filter, a codec connected to the output of the transmission-medium-emulating filter, a combiner for subtracting the output of the codec from the output of the transmission-medium-emulating filter, a band limiting filter responsive to an output signal of the combiner, and an input subtracter, for subtracting the output of the band limiting filter from incoming signals to form a symbol signal, the symbol signal being applied to the switched filter and to A/D means for developing said digital string.

Claim 20

Dependent Claim 169 words

An modem including a transmitting section for developing an analog signal in response to an applied digital stream, which analog signal is destined to a remote clocked conversion means, a receiving section for developing a digital string in response to an analog signal from the remote clocked conversion means, means for developing a clock in synchronism with the clock in the remote conversion means, and means for employing the developed clock in the transmitting section, the receiving section comprising: a switched filter, a transmission-medium-emulating filter responsive the output of the switched filter, a codec connected to the output of the transmission-medium-emulating filter, a combiner for subtracting the output of the codec from the output of the transmission-medium-emulating filter, a band limiting filter responsive to an output signal of the combiner, and an input subtracter, for subtracting the output of the band limiting filter from incoming signals to form a symbol signal, the symbol signal being applied to the switched filter and to A/D means for developing said digital string.

Claim 21

Independent Claim 143 words

A method for modifying operational parameters of a modem connected to a digital channel bank via analog lines, where the modem has a receiving portion and a transmitting portion, the method comprising the steps of: connecting the modem, through the channel bank, to a predefined destination, which connecting is effected over digital facilities following the channel bank, having communication and signal processing capabilities, the modem receiving a known signal, through the digital facilities through the channel bank, from the predefined destination, the modem processing the received signal to develop first control signals for the receiving portion and second control signals for the transmitting portion, the modem equalizing the receiving portion in response to the first control signals developed by the step of processing, and the modem equalizing the transmitting portion in response to the second control signals developed by the step of processing.

Claim 22

Independent Claim 143 words

A method for modifying operational parameters of a modem connected to a digital channel bank via analog lines, where the modem has a receiving portion and a transmitting portion, the method comprising the steps of: connecting the modem, through the channel bank, to a predefined destination, which connecting is effected over digital facilities following the channel bank, having communication and signal processing capabilities, the modem receiving a known signal, through the digital facilities through the channel bank, from the predefined destination, the modem processing the received signal to develop first control signals for the receiving portion and second control signals for the transmitting portion, the modem equalizing the receiving portion in response to the first control signals developed by the step of processing, and the modem equalizing the transmitting portion in response to the second control signals developed by the step of processing.

Annuity Stage	Window Opens	Payment Deadline	Surcharge Period Until	Estimated Fee	Status
3.5 Years (Year 4)	1998-02-27	1998-08-29	1999-02-28	$2000.00	Window Closed / Lapsed
7.5 Years (Year 8)	2002-02-27	2002-08-29	2003-02-28	$3760.00	Window Closed / Lapsed
11.5 Years (Year 12)	2006-02-27	2006-08-29	2007-02-28	$7700.00	Window Closed / Lapsed

High-speed modem synchronized to a remote CODEC

Abstract

Inventors

Bibliographic Details

Claims Analysis

References Cited (Backward Citations)

USPTO Annuity & Maintenance Windows

Assigned Categories & Tags

Assign Category Tag