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    Digital circuit discriminator for frequency-shift data signals
    3.
    发明授权
    Digital circuit discriminator for frequency-shift data signals 失效
    用于频移数据信号的数字电路鉴别器

    公开(公告)号：US3636454A

    公开(公告)日：1972-01-18

    申请号：US3636454D

    申请日：1970-07-28

    Applicant: BELL TELEPHONE LABOR INC

    Inventor： PASTERNACK GERALD PHILIP ,  SALTZBERG BURTON R

    IPC: H04L27/14 ,  H03K9/06

    CPC classification number: H04L27/14

    Abstract: FSK data signals are applied to a phase-locked loop whose binary signal output has an average amplitude which varies with the frequency of the incoming data signal. A zero-crossing detector produces a pulse for each zero crossing of the binary signal and the pulses are processed by a transversal digital filter having finite memory and arranged to provide triangular weighting to each input pulse. The baseband signal is then recovered from the filter output. In one embodiment, the zero-crossing detector and the transversal filter are advantageously arranged to be time shared by a plurality of FSK signal channels.

    Digital frequency-shift modulator using a read-only-memory
    8.
    发明授权
    Digital frequency-shift modulator using a read-only-memory 失效
    使用只读存储器的数字频率调制器

    公开(公告)号：US3697892A

    公开(公告)日：1972-10-10

    申请号：US3697892D

    申请日：1971-02-19

    Applicant: BELL TELEPHONE LABOR INC

    Inventor： LAWRENCE THOMAS R ,  SALTZBERG BURTON R

    IPC: G06F1/03 ,  H04L27/12

    CPC classification number: G06F1/0321 ,  G06F2101/04 ,  H04L27/12

    Abstract: FSK signals in a digital sense are obtained from a memory comprising a table of forty numbers, representing amplitudes of points in one cycle of a sine wave, the points being separated by equal phase angles. A processor reads out, at a fixed rate, the numbers corresponding to each tenth or each eleventh point in accordance with the condition of an incoming binary signal, whereby the output numbers represent a frequency-shift wave. Digital circuitry is used and the modulator may be time shared by a plurality of data sources.

    Abstract translation: 从数字意义上的FSK信号是从包含四十个数字的表的存储器获得的，表示正弦波的一个周期中的点的振幅，这些点被相等相位角分隔。 处理器以固定速率根据输入二进制信号的条件读出对应于每十位或第十一点的数字，由此输出数字表示频移波。 使用数字电路，并且调制器可以由多个数据源进行时间共享。

    Digital filter receiver for frequency-shift data signals
    9.
    发明授权
    Digital filter receiver for frequency-shift data signals 失效
    用于频移数据信号的数字滤波接收器

    公开(公告)号：US3689844A

    公开(公告)日：1972-09-05

    申请号：US3689844D

    申请日：1969-12-11

    Applicant: BELL TELEPHONE LABOR INC

    Inventor： BUZZARD CLAIR A ,  SALTZBERG BURTON R

    IPC: H04L27/156 ,  H04B1/16

    CPC classification number: H04L27/1566

    Abstract: Sampled FSK data signals are converted to multibit numbers and processed by a digital filter receiver which includes a band-pass filter, a dual-resonator discriminator and a low-pass filter. The dc baseband data signal is reconstructed from the receiver output number by a ''''slicer'''' which detects the sign of the output numbers. The analog-to-number conversion is simplified by limiting the multibit numbers to be processed to two values, simulating the hard limiting of analog signals. Signal harmonics introduced by the nonlinearities of the analog-to-digital converter are substantially eliminated by fixing the sampling rate to a rate which interleaves, in the frequency spectrum, the filter aliases with the harmonies. The receiver is advantageously arranged to be time-shared by a plurality of channels.

    Abstract translation: 采样的FSK数据信号被转换成多位数，并由包括带通滤波器，双谐振器鉴别器和低通滤波器的数字滤波器接收器进行处理。 直接基带数据信号通过检测输出数字的符号的“切片器”从接收器输出数重建。 通过将要处理的多位数字限制为两个值来简化模数转换，模拟模拟信号的硬限制。 由模数转换器的非线性引入的信号谐波基本上通过将采样率固定为在频谱中与谐波进行滤波的别名的速率来消除。 接收机有利地被布置成由多个信道共享时间。

    Digital filter frequency-shift modulator
    10.
    发明授权
    Digital filter frequency-shift modulator 失效
    数字滤波频率调制器

    公开(公告)号：US3671670A

    公开(公告)日：1972-06-20

    申请号：US3671670D

    申请日：1970-04-15

    Applicant: BELL TELEPHONE LABOR INC

    Inventor： SALTZBERG BURTON R

    IPC: H04L27/12 ,  H04B1/04

    CPC classification number: H04L27/12

    Abstract: Unity gain feedback places a second-order digital filter on the borderline of stability. The filter therefore oscillates in a numerical sense. Two feedback multipliers, each capable of determining a different central coefficient (and thus different oscillation frequencies) are alternatively inserted into an independent feedback path under control of an input baseband data signal whereby the output frequency is shifted in accordance with the input data. Phase discontinuities and amplitude variations due to the frequency shift are eliminated by extracting the numbers stored in the filter when a data transition occurs and reinserting new numbers representing samples of the new frequency wave, the new numbers further defining points on the new wave having the same instantaneous amplitude and phase as the wave samples defined by the extracted numbers.

    Abstract translation: Unity增益反馈将二阶数字滤波器置于稳定性的边界。 因此，滤波器在数值上会振荡。 在输入基带数据信号的控制下，可以将两个能够确定不同的中心系数（以及因此不同的振荡频率）的反馈乘法器插入到独立的反馈路径中，从而根据输入数据移位输出频率。 当数据转换发生时，通过提取存储在滤波器中的数字并重新插入表示新频率波的样本的新数字，消除了频移的相位不连续性和振幅变化，新数字进一步限定新波上的点相同 作为由提取的数字定义的波样本的瞬时振幅和相位。

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