High density digital transmission system

Claim 2

In a band limited high density digital transmission system operating in combination with input and output signal processing means, the combination which comprises: (a) a transmitter adapted to be connected to said input processing means, (b) a receiver adapted to be connected to said output processing means, (c) said transmitter including a modulator having an active pulse forming network and a bandlimiting passive pulse shaping network and said receiver including a detector having a bandlimiting passive pulse shaping network, said networks including means to produce specified output pulse shapes from receiver input pulses, with said receiver input pulse shapes generated by said transmitter passive pulse shaping network operating on specified input pulse shapes generated by said transmitter active pulse shaping network, (d) the signal channel comprising said transmitter and receiver having a channel function H c (jω) which is the Fourier transform of the desired output pulse in accordance with the relation H.sub.c (jω) = H.sub.TX (jω)H.sub.RX (jω), said bandlimiting passive pulse shaping network of said receiver having the function H RX which is the complex conjugate of the function H TX , where H.sub.TX (jω) = |H.sub.c (jω)| .sup.1/2 e.sup.jθ(ω) and H.sub.RX (jω) = |H.sub.c (jω)|.sup.1/2 e.sup.-jθ(ω) wherein H TX (jω) is the product of the transmitter active pulse forming network pulse function, P(jω ), and the transfer function of the passive pulse shaping network, H T (jω), as H.sub.TX (jω) = P(jω)H.sub.T (jω) the transmitter and receiver pulse shaping networks both being specified by network poles and residues and time domain optimized for achieving specified input-to-output pulse shape transformation and minimizing adjacent channel interference where said transmitter and receiver passive pulse shaping networks are integral parts of the system modulation and detection means.

Claim 3

The system of claim 1 wherein said transmitter and receiver includes means for forming each successive receiver output pulse to have maximum value at the pulse sample time and equal to zero at all other sample times where said sample values are obtained from an output pulse shape approximating a raised cosine pulse.

Claim 4

The system of claim 2, wherein said transmitter active pulse forming network means is an eight phase PSK modulator means accommodating rectangular in-phase and quadrature phase modulating pulses with normalized amplitude values of ±1 or ±0.707 and where said receiver partition includes an eight phase PSK demodulator means.

Claim 5

The system of claim 3, wherein the transmitter bandlimiting passive pulse shaping network means and the receiver bandlimiting pulse shaping network means are all-pole filter means concatenated with all-pass equalizer means.

Claim 6

The system of claim 3, wherein the transmitter bandlimiting passive pulse shaping network means and the receiver bandlimiting pulse shaping network means are equal-ripple stopband filter means concatenated with all-pass equalizer means.

Claim 7

The system of claim 2, wherein said transmitter active pulse forming network includes means to modulate in-phase and quadrature phase (I and Q channel) carriers with time coincident rectangular pulses with normalized amplitudes of ±1, ±3, ±5 . . . ±k yielding k+1 (k=1,3,5 . . . ) output levels on each of said I and Q channels; where receiver includes independent I and Q channel detection means with phase coherent reference signals at the received signal spectrum center frequency, said reference signals displaced 90° from each other; said separate I and Q channel detectors being followed by low-pass filters and sampling detectors each operating at a rate of 1/T where T is the channel signalling rate; and an output signal processing circuit for sample value decoding the outputs of said detectors and combining the same into a single output data stream.

Claim 8

The system of claim 6, wherein the transmitter bandlimiting passive pulse shaping network means and the receiver bandlimiting pulse shaping network means are all-pole filter means concatenated with all-pass equalizer means.

Claim 9

The system of claim 6, wherein the transmitter bandlimiting passive pulse shaping network means and the receiver bandlimiting pulse shaping network means are equal-ripple stopband filter means concatenated with all-pass equalizer means.

Claim 10

The system of claim 2, wherein said transmitter active pulse forming network includes means to modulate in-phase and quadrature phase (I and Q channel) carriers with time offset rectangular pulses with normalized amplitude values of ±1, ±3, ±5, . . . ±k yielding k+1 levels on each of said I and Q channels.

Claim 11

The system of claim 9, wherein said receiver includes a signal detection means using a single phase coherent reference displaced ±1/4T from the received signal spectrum center frequency where T is the channel signalling interval, said detection means being followed by a low-pass filter and a single sampling circuit operating at a rate of 2/T with alternate sample values equal to I and Q channel data values, respectively, and with the algebraic signs on alternate sample values for each individual channel reversed, and an output signal processing circuit for sample value decoding the output of said sampling detectors.

Claim 12

The system of claim 10, wherein the transmitter bandlimiting passive pulse shaping network means and the receiver bandlimiting pulse shaping network means are all-pole filter means concatenated with all-pass equalizer means.

Claim 13

The system of claim 10, wherein the transmitter bandlimiting passive pulse shaping network means and the receiver bandlimiting pulse shaping network means are equal-ripple stopband filter means concatenated with all-pass equalizer means.

Claim 14

The system of claim 9, wherein said receiver includes a signal detector means using separate I and Q channel detectors with phase coherent reference signals at the received signal spectrum center frequency, said reference signals displaced 90° from each other and with said separate I and Q channel detectors followed by low-pass filters and sampling detectors each operating at a rate of 1/T where T is the channel signalling interval, an output signal processing circuit for sample value decoding the outputs of said sampling detectors and combining the same into a single output data stream.

Claim 15

The system of claim 13, wherein the transmitter bandlimiting passive pulse shaping network means and the receiver bandlimiting pulse shaping network means are all-pole filter means concatenated with all-pass equalizer means.

Claim 16

The system of claim 13, wherein the transmitter bandlimiting passive pulse shaping network means and the receiver bandlimiting pulse shaping network means are equal-ripple stopband filter means concatenated with all-pass equalizer means.

Claim 17

The system of claim 2, wherein said active pulse forming network includes means to modulate in-phase and quadrature phase (I and Q channel) carriers with time offset half-wave sinusoidal pulses with normalized peak amplitude values of ±1, ±3, ±5, . . . ±k, in a systems approach yielding k+1 peak levels on each of said I and Q channels.

Claim 18

The system of claim 16, wherein said receiver includes a signal detection means using a single phase coherent reference displaced ±1/4T from the received signal spectrum center freqeuncy where T is the channel signalling interval, said detection means being followed by a low-pass filter and a single sampling circuit operating at a rate of 2/T with alternate sample value equal to I and Q channel data values, respectively, and with the algebraic signs on alternate sample values for each individual channel reversed, and an output signal processing circuit for sample value decoding the output of said sampling detectors.

Claim 19

The system of claim 17, wherein the transmitter bandlimiting passive pulse shaping network means and the receiver bandlimiting pulse shaping network means are all-pole filter means concatenated with all-pass equalizer means.

Claim 20

The system of claim 17, wherein the transmitter bandlimiting passive pulse shaping network means and the receiver bandlimiting pulse shaping network means are equal-ripple stopband filter means concatenated with all-pass equalizer means.

Claim 21

The system of claim 16, wherein said receiver includes a signal detector means using separate I and Q channel detectors with phase coherent reference signals at the received signal spectrum center frequency, said reference signals displaced 90° from each other and with said separate I and Q channel detectors followed by low-pass filters and sampling detectors each operating at a rate of 1/T where T is the channel signalling interval, and an output signal processing circuit for sample value decoding the outputs of said sampling detectors and combining the same into a single output data stream.

Claim 22

The system of claim 20, wherein the transmitter bandlimiting passive pulse shaping network means and the receiver bandlimiting pulse shaping network means are all-pole filter means concatenated with all-pass equalizer means.

Claim 23

The system of claim 20, wherein the transmitter bandlimiting passive pulse shaping network means and the receiver bandlimiting pulse shaping network means are equal-ripple stopband filter means concatenated with all-pass equalizer means.

Claim 24

The system of claim 1 wherein said transmitter and receiver includes means for forming each successive receiver output pulse to have equal values at two successive pulse sample times and equal to zero at all other sample times, thereby yielding output sample values equal to the sum of two successive pulse values, where said sample values are obtained from an output pulse shape approximating a partial response pulse.

Claim 25

The system of claim 23, wherein said transmitter active pulse forming network includes means to modulate in-phase and quadrature phase (I and Q channel) carriers with time coincident rectangular pulses with normalized amplitudes of ±1, ±3, ±5, . . . ±k yielding 2k+1 output levels on each of said I and Q channels; with said receiver including independent I and Q channel detection means with phase coherent reference signals at the received signal spectrum center frequency, said reference signals displaced 90° from each other; said separate I and Q channel detectors being followed by low-pass filters and sampling detectors each operating at a rate of 1/T where T is the channel signalling rate; and an output signal processing circuit for sample value decoding the outputs of said detectors and combining the same into a single output data stream. pg,61

Claim 26

The system of claim 24, wherein the transmitter bandlimiting passive pulse shaping network means and the receiver bandlimiting pulse shaping network means are all-pole filter means concatenated with all-pass equalizer means.

Claim 27

The system of claim 24, wherein the transmitter bandlimiting passive pulse shaping network means and the receiver bandlimiting pulse shaping network means are equal-ripple stopband filter means concatenated with all-pass equalizer means.

Claim 28

The system of claim 23, wherein said transmitter active pulse forming network includes means to modulate in-phase and quadrature phase (I and Q channel) carriers with time offset rectangular pulses with normalized sample values of ±1, ±3, ±5, . . . ±k yielding 2k+1 levels on each of said I and Q channels.

Claim 29

The system of claim 27, wherein said receiver includes a signal detection means using a single phase coherent reference displaced ±1/4T from the received signal spectrum center frequency where T is the channel signalling interval, said detection means being followed by a low-pass filter and a single sampling circuit operating at a rate of 2/T with alternate sample values equal to I and Q channel data values, respectively, and with the algebraic signs on alternate sample values for each individual channel reversed, and an output signal processing circuit for sample value decoding the output of said sampling detectors.

Claim 30

The system of claim 28, wherein the transmitter bandlimiting passive pulse shaping network means and the receiver bandlimiting pulse shaping network means are all-pole filter means concatenated with all-pass equalizer means.

Claim 31

The system of claim 28, wherein the transmitter bandlimiting passive pulse shaping network means and the receiver bandlimiting pulse shaping network means are equal-ripple stopband filter means concatenated with all-pass equalizer means.

Claim 32

The system of claim 27, wherein said receiver includes a signal detector means using separate I and Q channel detectors with phase coherent reference signals at the received signal spectrum center frequency, said reference signals displaced 90° from each other and with said separate I and Q channel detectors followed by low-pass filters and sampling detectors each operating at a rate of 1/T and T is the channel signalling interval, and an output signal processing circuit for sample value decoding the outputs of said sampling detectors and combining the same into a single output data stream.

Claim 33

The system of claim 31, wherein the transmitter bandlimiting passive pulse shaping network means and the receiver bandlimiting pulse shaping network means are all-pole filter means concatenated with all-pass equalizer means.

Claim 34

The system of claim 31, wherein the transmitter bandlimiting passive pulse shaping network means and the receiver bandlimiting pulse shaping network means are equal-ripple stopband filter means concatenated with all-pass equalizer means.

Claim 35

The system of claim 23, wherein said active pulse forming network includes means to modulate in-phase and quadrature phase (I and Q channel) carriers with time offset half-wave sinusoidal pulses with normalized peak amplitude values of ±1, ±3, ±5, . . . ±k, yielding 2k+1 peak output levels on each of said I and Q channels.

Claim 36

The system of claim 34, wherein said receiver includes a signal detection means using a single phase coherent reference displaced ±1/4T from the received signal spectrum center frequency where T is the channel signalling interval, said detection means being followed by a low-pass filter and a single sampling circuit operating at a rate of 2/T with alternate sample values equal to I and Q channel data values, respectively, and with the algebraic signs on alternate sample values for each individual channel reversed, and an output signal processing circuit for sample value decoding the outputs of said sampling detectors.

Claim 37

The system of claim 35, wherein the transmitter bandlimiting passive pulse shaping network means and the receiver bandlimiting pulse shaping network means are all-pole filter means concatenated with all-pass equalizer means.

Claim 38

The system of claim 35, wherein the transmitter bandlimiting passive pulse shaping network means and the receiver bandlimiting pulse shaping network means are equal-ripple stopband filter means concatenated with all-pass equalizer means.

Claim 39

The system of claim 34, wherein said receiver includes a signal detector means using separate I and Q channel detectors with phase coherent reference signals at the received signal spectrum center frequency, said reference signals displaced 90° from each other and with said separate I and Q channel detectors followed by low-pass filters and sampling detectors each operating at a rate of 1/T where T is the channel signalling interval, and an output signal processing circuit for sample value decoding the outputs of said sampling detectors and combining the same into a single output data stream.

Claim 40

The system of claim 38, wherein the transmitter bandlimiting passive pulse shaping network means and the receiver bandlimiting pulse shaping network means are all-pole filter means concatenated with all-pass equalizer means.

Claim 41

The system of claim 38, wherein the transmitter bandlimiting passive pulse shaping network means and the receiver bandlimiting pulse shaping networks means are equal-ripple stopband filter means concatenated with all-pass equalizer means.

Claim 42

In a transmitter system for use in a high density bandlimited digital transmission system for use with a receiver having a pulse shaping network; (a) an active pulse shaping network for generating modulated output pulses in response to data input from a precoder and frequency input from a stable frequency source; (b) a passive pulse shaping network connected to accept input from the said active pulse shaping network and related to said receiver pulse shaping network to assure specified receiver output pulses with controlled intersymbol interference and predetermined suppression of adjacent channel interference; (c) a transmitter output system accepting input from said passive pulse shaping network and said stable frequency source for producing an output signal for transmission to said receiver where the composite channel function H c (jω) is the Fourier transform of the desired output pulse and is given by H.sub.c (jω) = H.sub.TX (jω) H.sub.RX (jω) matching the receiver filter performance with the receiver filter function being the complex conjugate of the transmitter function H.sub.TX (jω) = |H.sub.c (jω)|.sup.1/2 e.sup.jθ (ω) H.sub.RX (jω) = |H.sub.c (jω)|.sup.1/2 e.sup.- jθ(ω) with H TX (jω) being realized as the product of the transmitter active pulse forming network pulse function, P(jω), and the transfer function of the passive pulse shaping network, H T (jω), as H.sub.TX (jω) = P(jω) H.sub.T (jω); and where said transmitter passive pulse forming network is specified by the network poles and residues enabling time domain optimization of the end-to-end channel response in achieving the specified input-to-output pulse shape transformation while meeting specified adjacent channel interference attenuation where said transmitter passive pulse shaping filter means thus is an integral part of the system modulation.

Claim 43

In a transmitter system for use in a high density bandlimited digital transmission system for use with a receiver having a pulse shaping network; (a) an active pulse shaping network for generating modulated output pulses in response to data input from a precoder and frequency input from a stable frequency source; (b) a passive pulse shaping network connected to accept input from the said active pulse shaping network and related to said receiver pulse shaping network to assure specified receiver output pulses with controlled intersymbol interference and predetermined suppression of adjacent channel interference; (c) a transmitter output system accepting input from said passive pulse shaping network and said stable frequency source for producing an output signal for transmission to said receiver where the composite channel function H c (jω) is the Fourier transform of the desired output pulse and is given by H.sub.c (jω) = H.sub.TX (jω) H.sub.RX (jω) matching the receiver filter performance with the receiver filter function being the complex conjugate of the transmitter function H.sub.TX (jω) = |H.sub.c (jω)|.sup.1/2 e.sup.jθ (ω) H.sub.RX (jω) = |H.sub.c (jω)|.sup.1/2 e.sup.- jθ(ω) with H TX (jω) being realized as the product of the transmitter active pulse forming network pulse function, P(jω), and the transfer function of the passive pulse shaping network, H T (jω), as H.sub.TX (jω) = P(jω) H.sub.T (jω); and where said transmitter passive pulse forming network is specified by the network poles and residues enabling time domain optimization of the end-to-end channel response in achieving the specified input-to-output pulse shape transformation while meeting specified adjacent channel interference attenuation where said transmitter passive pulse shaping filter means thus is an integral part of the system modulation.

Claim 44

The transmitter system of claim 41, wherein said transmitter active pulse forming network means is an eight phase PSK modulator means with rectangular in-phase and quadrature phase modulating pulses with normalized amplitude values of ±1.0 or ±0.707 and with said receiver partition including an eight phase PSK demodulator means.

Claim 45

The transmitter system of claim 41, wherein said transmitter active pulse forming network modulates in-phase and quadrature phase (I and Q channel) carriers with time coincident rectangular pulses with normalized amplitudes of ±1, ±3, ±5 . . . ±k yielding k+1 (k=1,3,5 . . . ) output levels on each of said I and Q channels.

Claim 46

The transmitter system of claim 41, wherein said transmitter active pulse forming network modulates in-phase and quadrature phase (I and Q channel) carriers with time offset rectangular pulses with normalized amplitude values of ±1, ±3, ±5 . . . ±k yielding k+1 levels on each of said I and Q channels.

Claim 47

The transmitter system of claim 41, wherein said active pulse forming network modulates in-phase and quadrature phase (I and Q channel) carriers with time offset half-wave sinusoidal pulses with normalized peak amplitude values of ±1, ±3, ±5, . . . ±k, in a systems approach yielding k+1 peak levels on each of said I and Q channels.

Claim 48

In a receiver system for use in high density bandlimited digital transmission from a transmitter having a passive pulse shaping network; a receiver input system for accepting a received RF input signal and a frequency reference signal from a timing and frequency recovery circuit and for producing an amplifier output signal for further receiver processing; a receiver pulse shaping network for accepting as input the output from said receiver input system and operating in combination with said transmitter passive pulse shaping network to produce output pulses with controlled intersymbol interference and predetermined suppression of adjacent channel interference, said receiver pulse shaping network also including means for providing inputs to said timing and frequency recovery circuit; a detection and decoding system for accepting as its input the output from the receive pulse shaping network and including means to sample said output in synchronism with a clock signal supplied from the timing and frequency recovery means producing sample values which are decoded into output data values; with the composite channel function H c (jω) being the Fourier transform of the desired output pulse and being given by H.sub.c (jω) = H.sub.TX (jω) H.sub.RX (jω) with optimal channel partitioning yielding matched filter receiver performance with the receiver function being the complex conjugate of the transmitter function yielding H.sub.TX (jω) = |H.sub.c (jω)|.sup.1/2 e.sup. jθ(ω) H.sub.RX (jω) = |H.sub.c (jω)|.sup.1/2 e.sup.-jθ(ω) with H TX (jω) being realized as the product of the transmitter active pulse forming network pulse function, P(jω), and the transfer function of the passive pulse shaping network, H T (jω ), as H.sub.TX (jω) = P(jω) H.sub.T (jω); and transmitter and receiver passive pulse forming network means being specified by the network poles and residues enabling time domain optimization of the end-to-end channel response in achieving the specified input-to-output pulse shape transformation while meeting specified adjacent channel interference attenuation; said transmitter and receiver passive pulse shaping filter means thus being an integral part of the system modulation and detection means.

Claim 49

In a receiver system for use in high density bandlimited digital transmission from a transmitter having a passive pulse shaping network; a receiver input system for accepting a received RF input signal and a frequency reference signal from a timing and frequency recovery circuit and for producing an amplifier output signal for further receiver processing; a receiver pulse shaping network for accepting as input the output from said receiver input system and operating in combination with said transmitter passive pulse shaping network to produce output pulses with controlled intersymbol interference and predetermined suppression of adjacent channel interference, said receiver pulse shaping network also including means for providing inputs to said timing and frequency recovery circuit; a detection and decoding system for accepting as its input the output from the receive pulse shaping network and including means to sample said output in synchronism with a clock signal supplied from the timing and frequency recovery means producing sample values which are decoded into output data values; with the composite channel function H c (jω) being the Fourier transform of the desired output pulse and being given by H.sub.c (jω) = H.sub.TX (jω) H.sub.RX (jω) with optimal channel partitioning yielding matched filter receiver performance with the receiver function being the complex conjugate of the transmitter function yielding H.sub.TX (jω) = |H.sub.c (jω)|.sup.1/2 e.sup. jθ(ω) H.sub.RX (jω) = |H.sub.c (jω)|.sup.1/2 e.sup.-jθ(ω) with H TX (jω) being realized as the product of the transmitter active pulse forming network pulse function, P(jω), and the transfer function of the passive pulse shaping network, H T (jω ), as H.sub.TX (jω) = P(jω) H.sub.T (jω); and transmitter and receiver passive pulse forming network means being specified by the network poles and residues enabling time domain optimization of the end-to-end channel response in achieving the specified input-to-output pulse shape transformation while meeting specified adjacent channel interference attenuation; said transmitter and receiver passive pulse shaping filter means thus being an integral part of the system modulation and detection means.

Claim 50

The receiver system of claim 46, wherein each successive receiver output pulse has maximum value at the pulse sample time and is equal to zero at all other sample times with said sample values being realized with an output pulse shape approximating a raised cosine pulse.

Claim 51

The receiver system of claim 47, wherein said receiver demodulates independent received I and Q data channel with time-offset modulating pulses using a single phase coherent reference displaced ±1/4T from the received signal spectrum center frequency where T is the channel signalling interval, said detection means being followed by a low-pass filter and a single sampling circuit operating at a rate of 2/T with alternate sample values equal to I and Q channel data values, respectively, and with the algebraic signs on alternate sample values for each individual channel reversed, and with the output of said sampling detectors being fed to output signal processing circuitry means for sample value decoding.

Claim 52

The receiver system of claim 47, wherein said receiver includes a signal detector means using separate I and Q channel detectors with phase coherent reference signals at the received signal spectrum center frequency, said reference signals displaced 90° from each other and with said separate I and Q channel detectors followed by low-pass filters and sampling detectors each operating at a rate of 1/T where T is the channel signalling interval, the outputs of said sampling detectors being fed to output signal processing circuitry means for sample value decoding and combination into a single output data stream.

Claim 53

The receiver system of claim 46, wherein each successive receiver output pulse has equal values at two successive pulse sample times and is equal to zero at all other sample times, thereby yielding output sample values equal to the sum of two successive pulse values, said sample values being realized with an output pulse shape approximating a partial response pulse.

Claim 54

The receiver system of claim 50, wherein said receiver includes means to demodulate independent received I and Q data channel with time-offset modulating pulses using a single phase coherent reference displaced ±1/4T from the received signal spectrum center frequency where T is the channel signalling interval, said detection means being followed by a low-pass filter and a single sampling circuit operating at a rate of 2/T with alternate sample values equal to I and Q channel data values, respectively, and with the algebraic signs of alternate sample values for each individual channel reversed, and means to feed the output of said sampling detectors to an output signal processing circuit for sample value decoding.

Claim 55

The receiver system of claim 50, wherein said receiver includes a signal detector means using separate I and Q channel detectors with phase coherent reference signals at the received signal spectrum center frequency, said reference signals displaced 90° from each other and with said separate I and Q channel detectors followed by low-pass filters and sampling detectors each operating at a rate of 1/T where T is the channel signalling interval, the outputs of said sampling detectors being fed to output signal processing circuitry means for sample value decoding and combination into a single output data stream.

Claim 56

In a band limited high density digital transmission system operating in combination with input and output signal processing means, the combination which comprises: (a) a transmitter adapted to be connected to said input processing means, (b) a receiver adapted to be connected to said output processing means, (c) said transmitter including a modulator having an active pulse forming network and a bandlimiting passive pulse shaping network and said receiver including a detector having a bandlimiting passive pulse shaping network, said networks including means to produce specified output pulse shapes from receiver input pulses, with said receiver input pulse shapes generated by said transmitter passive pulse shaping network operating on specified input pulse shapes generated by said transmitter active pulse shaping network, (d) the signal channel comprising said transmitter and receiver having a channel function H c (jω ) which is the Fourier transform of the desired output pulse in accordance with the relation H.sub.c (jω) = H.sub.TX (jω)H.sub.RX (jω), wherein H TX (jω ) is the product of the transmitter active pulse forming network pulse function, P(jω ), and the transfer function of the passive pulse shaping network, H T (jω ), as H.sub.TX (jω) = P(jω)H.sub.T (jω) the transmitter and receiver pulse shaping networks both being specified by network poles and residues and time domain optimized for achieving specified input-to-output pulse shape transformation and minimizing adjacent channel interference where said transmitter and receiver passive pulse shaping networks are integral parts of the system modulation and detection means.

Claim 57

In a band limited high density digital transmission system operating in combination with input and output signal processing means, the combination which comprises: (a) a transmitter adapted to be connected to said input processing means, (b) a receiver adapted to be connected to said output processing means, (c) said transmitter including a modulator having an active pulse forming network and a bandlimiting passive pulse shaping network and said receiver including a detector having a bandlimiting passive pulse shaping network, said networks including means to produce specified output pulse shapes from receiver input pulses, with said receiver input pulse shapes generated by said transmitter passive pulse shaping network operating on specified input pulse shapes generated by said transmitter active pulse shaping network, (d) the signal channel comprising said transmitter and receiver having a channel function H c (jω ) which is the Fourier transform of the desired output pulse in accordance with the relation H.sub.c (jω) = H.sub.TX (jω)H.sub.RX (jω), wherein H TX (jω ) is the product of the transmitter active pulse forming network pulse function, P(jω ), and the transfer function of the passive pulse shaping network, H T (jω ), as H.sub.TX (jω) = P(jω)H.sub.T (jω) the transmitter and receiver pulse shaping networks both being specified by network poles and residues and time domain optimized for achieving specified input-to-output pulse shape transformation and minimizing adjacent channel interference where said transmitter and receiver passive pulse shaping networks are integral parts of the system modulation and detection means.