[ 0017 ] fig1 shows a block diagram of the transmitter , according to an embodiment of the present invention . the digital information source is shown as the block 10 . the mpsk modulator 11 modulates the digital source waveform to the desired mpsk signals ( e . g ., bpsk , qpsk , 8psk , 16psk etc ) for transmission . to improve the ber performance , we can also use multiple cycles per symbol ( e . g ., 4 cycles per symbol etc ) to encode each symbol . the modulated signal 12 is then amplified and / or wave shaped or up - converted to suitable wave 14 before being sent to the communication channel . the channel can be wire - line or wireless . in fig1 an antenna 15 is shown for the case of a wireless channel . [ 0019 ] fig2 shows the receiver system of the invention . for the case of a wireless channel , the system comprises an antenna 210 which receives the mpsk modulated transmitted signal . the received signals may pass through an optional amplifier and / or wave shaper circuit , or down - converter 200 to condition the incoming signal to make it suitable for optimum detection by the subsequent circuit . the conditioned signal 201 from the circuit 200 is then fed to a nonlinear circuit combination 206 , comprising an inductor 203 connected in series to a circuit 204 . the circuit 204 has an n - shaped i - v characteristic as shown in fig3 with the impasse points positioned as shown . the lower impasse point is located at a small positive voltage . the output 202 from the circuit 204 comprises groups of pulses or periods of silence depending on the received signals . a gating circuit 209 and a pulse processing circuit 207 then determine the appropriate decoded digital signal 208 based on the received groups of pulses . the gating circuit sets suitable timing windows which are temporally aligned with the information waveform at the transmitting end of a communication system . the gating function serves to mask out those pulses which do not correspond to the pulses in the original information waveform , while leaving the remaining groups of pulses which correspond to the information waveform intact . by detecting the number of pulses in each group , we can reproduce the symbols represented by the information waveform . this approach improves the receiver ber performance substantially . in the case of bpsk signals , two gating circuits are used , each with a different gating window as shown in fig4 . the characteristic curve of the circuit 204 is shown in fig3 . the transfer curve has two impasse points p 1 =( v v , i v ) and p 3 =( v p , i p ). here , i v and i p represent the valley and the peak current of the n curve . in general , we do not require that the curves be piecewise linear . the only requirement is that the characteristic curve consists of three distinct regions such that the middle region is having negative impedance slope , while the two external regions are having positive impedance slopes . under the condition that the input signal is operating at the line segment p 1 - p 3 of the characteristic curve , pulses will be generated which traveled along the state trajectory p 4 p 3 p 2 p 1 p 4 . the number of pulses being generated depends on the available time ( i . e ., the duration that the input signal is operating on the line segment p 1 - p 3 ) and the speed of the trajectory . referring now to fig5 we show another receiver configuration that is used in the form of dual detector mode . in this illustrative embodiment of the invention , a duo detector configuration is shown and it can also be extended to multiple detector configurations . the i - v characteristics of each n - type circuit may be constructed to have different set of impasse points , so that it responds to the input signals differently than another of the n - type circuits , which is characterized by its own set of impasse points . similar to the single detector system , the second detector circuit 512 also consists of an inductor 509 and another nonlinear circuit 510 connected in series . the nonlinear circuit 5 10 also has an n - type i - v transfer characteristics . however , the transfer curve is positioned at different location by applying suitable voltage at the input 511 , and biasing etc . the input 504 and 511 can also be used to dynamically manipulate the transfer curves . the output from the circuit 512 also consists of a series of pulses or silences depending on the received signals . as the transfer curves of the circuits 505 and 512 are different , they responded to the same input signal 501 differently . the pulse processing circuit counts the number of pulses that occur in each gating circuit outputs and form a metric . based on the values of the metric , it determines which is the most likely symbol being transmitted . next , we describe the response of the system in fig5 . in the following , we first explain using m = 2 - ary bpsk modulation scheme . [ 0028 ] fig6 illustrates a typical response of the receiver shown in fig4 based on numerical simulation . the waveform 601 is the symbol to be transmitted . in this illustrative example , the signal that is being transmitted is the symbol { 1 2 1 1 }. the bpsk signal is shown as the waveform 602 . due to the additive white gaussian noise presence in the channel , the received signal is corrupted and is shown as the waveform 603 . the outputs from the two nonlinear circuits 505 and 512 comprise a series of pulses depending on the location of the signals as well as the level of the noises . this is shown as the waveform 604 and 605 for the positive and negative detectors in fig5 respectively . depending on the tuning of the nonlinear circuit , the presence of the digital signal can be set to generate a specified number of pulses . in this illustrative example , seven pulses are generated if a low noise signal is received . the waveform 606 shows the gating waveform for the symbol 1 . the gating waveform has two weighting values of ± 1 . the waveform 607 shows the signals after the gating function . upon receiving these pulses , the pulse processing system determines the decoded digital signals . essentially , the pulse processing system performs the following tasks : 1 . for each half cycle , calculate the metric of each symbol δ i , 0 ≦ i ≦ m − 1 , by summing the number of positive and negative pulses . 2 . compare the metrics of each symbol and decides that x m ( t ) is the most likely transmitted symbol if δ m is the largest amongst all the δ i . in this illustrative example shown in fig6 the decoded symbol is shown as 608 which is the same as the symbol sent . [ 0029 ] fig7 illustrates another example for the case of qpsk modulation scheme . in this case , the symbol that is being sent is { 4 1 3 2 } which is shown as 701 . the transmitted signal is shown as waveform 702 . the received waveform is shown as 703 . the pulses that are generated from the two n - type circuits are shown as 704 and 705 . the gating signals for the symbol 1 is shown as 706 . the resultant signals after the gating function is illustrated as 707 and the recovered symbols are shown as 708 . the bit error rate performance of the receiver can be improved by employing multiple cycle per symbol for the transmission . fig8 illustrates the response with four cycles per symbol based on the bpsk scheme . in the figure , the symbol that is being transmitted is the symbol set { 1 1 2 1 } shown as 801 . the bpsk signal is shown as 802 and the noisy received signal is 803 . pulses are generated at the output of the nonlinear circuits and are shown as 804 and 805 . these pulses are passed through gating circuits and the waveform 806 shows a gating signal for the symbol 1 . the resultant signal is shown as 807 and recovered symbols are shown as 808 .