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公开(公告)号：US4159398A
公开(公告)日：1979-06-26
申请号：US837256
申请日：1977-09-27
CPC分类号： H04H20/49
摘要： In an AM broadcast transmitter, an infrasonic tone is added to the difference channel of a compatible AM stereo system to provide a stereo presence signal. In a stereophonic receiver, the corrected output of a synchronous detector in the difference signal channel is coupled to an infrasonic detector for control of a mono/stereo mode switch and a stereo presence indicator. When the received signal is weak, the infrasonic tone is effectively stronger, because the phase angle is increased. Since the s/n ratio is proportional to the phase angle, the stereo presence signal is self-adjusting. The mode switch and indicator are enabled for all values of L and R. The infrasonic tone could also be removed from the transmitted signal whenever the difference signal goes above a predetermined level during stereo broadcasting, in which case a comparator at the receiver would enable the mode switch and indicator upon detection of either a difference signal or the infrasonic tone.
摘要翻译： 在AM广播发射机中，将不正常音调添加到兼容AM立体声系统的差分声道以提供立体声存在信号。 在立体声接收机中，差分信号通道中的同步检测器的校正输出耦合到用于控制单声道/立体声模式开关和立体声存在指示器的次声检测器。 当接收到的信号较弱时，由于相位角增加，所以下调声音实际上更强。 由于s / n比与相位角成比例，所以立体声存在信号是自调整的。 对于L和R的所有值，模式开关和指示器被使能。只要差分信号在立体声广播期间超过预定电平，也可以从发送信号中去除次声音，在这种情况下，接收机的比较器将使得 在检测到差分信号或者小音阶之间时，模式开关和指示灯。
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公开(公告)号：US4170716A
公开(公告)日：1979-10-09
申请号：US842026
申请日：1977-10-14
CPC分类号： H04H20/49
摘要： An AM receiver receiving a compatible stereo signal and utilizing a cosine correction signal for restoring the original stereo information limits the amount of correction at very large modulation angles to prevent excessive noise from being introduced by the increased gain.
摘要翻译： 接收兼容立体声信号的AM接收机和利用余弦校正信号恢复原始立体声信息的AM接收机在非常大的调制角度限制了校正量，以防止增加的增益引起过多的噪声。
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公开(公告)号：US4218586A
公开(公告)日：1980-08-19
申请号：US007733
申请日：1979-01-30
CPC分类号： H04H20/49
摘要： A compatible AM stereo broadcasting system is disclosed in which the signal is a carrier having an amplitude directly variable with monoaural or sum (L+R) information, and having an instantaneous phase .phi. varying as a function of the resultant amplitude of the sum information (L+R) and difference information (L-R) which are established in a preselected phase relationship (quadrature). In a stereo receiver, L and R or the sum and difference signals may be restored by dividing the signal by the cosine of the angle .phi., and in a monaural receiver, the sum signal alone is detected.
摘要翻译： 公开了一种兼容的AM立体声广播系统，其中所述信号是具有直接变化的幅度的载波，其具有单声道或和（L + R）信息，并且具有作为和信息的合成幅度的函数而变化的瞬时相位phi L + R）和以预选相位关系（正交）建立的差分信息（LR）。 在立体声接收机中，可以通过将信号除以角度phi的余弦来恢复和差和信号，并且在单声道接收机中，检测到和信号。
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公开(公告)号：US4172966A
公开(公告)日：1979-10-30
申请号：US880686
申请日：1978-02-23
CPC分类号： H04H20/49
摘要： An AM receiver for utilizing a broadcast signal of the form (1+L+R) cos (.omega..sub.c t+.phi.) separates the L and R signals by utilizing phase detection and matrixing. Distortion is either eliminated with non-linear amplification or reduced with partial matrixing.
摘要翻译： {PG，1 A AM接收机，用于利用形式的广播信号（1 {30 {i L {30 R {L）cos（{107 {hd c {it {1 {30 {100））分离L和R信号 通过利用相位检测和矩阵。 使用非线性放大消除失真，或者用部分矩阵法减少失真。
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公开(公告)号：US4159396A
公开(公告)日：1979-06-26
申请号：US837257
申请日：1977-09-27
CPC分类号： H04H20/49
摘要： A signal level controlled switching circuit removes the stereo correction factor in a compatible AM stereo receiver when the received signal level is low enough to allow signal degradation due to noise affecting the correction factor. The switching circuit can operate on either an instantaneous or an average signal level.
摘要翻译： 当接收的信号电平足够低以允许由于影响校正因子的噪声引起的信号劣化时，信号电平控制切换电路去除兼容的AM立体声接收机中的立体声校正因子。 开关电路可以在瞬时或平均信号电平上工作。
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公开(公告)号：US4406922A
公开(公告)日：1983-09-27
申请号：US295185
申请日：1981-08-21
CPC分类号： H04H20/88
摘要： The signal transmitted is a compatible amplitude modulated carrier with amplitude directly proportional to the monaural information or 1+L+R up to a frequency near the upper end of the normal program spectrum. Above the transition region, the amplitude becomes a pure quadrature function. The instantaneous phase varies as a function of the quadrature phase relationship. Transmitter and receiver embodiments are disclosed.
摘要翻译： 发射的信号是幅度调制载波，其幅度与单声道信息或1 + L + R成正比，直到接近正常节目频谱上端的频率。 在过渡区域之上，振幅变为纯正交函数。 瞬时相位作为正交相位关系的函数而变化。 公开了发射机和接收机实施例。
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公开(公告)号：US4338491A
公开(公告)日：1982-07-06
申请号：US156249
申请日：1980-06-04
CPC分类号： H04H20/49
摘要： The signal as transmitted is a compatible AM stereophonic signal with amplitude directly proportional to the monophonic signal 1+L+R. The instantaneous phase angle is the quadrature phase angle modified in that high level, high frequencies in the L-R channel are reduced before carrier modulation. The gain in the high frequency L - R channel may be reduced in proportion to the signal level only, or to both level and frequency, or to the percent of distortion introduced into the high frequencies of the L - R signal by RF filtering of the modulated carrier.
摘要翻译： 所发送的信号是具有与单声道信号1 + L + R成正比的幅度的兼容AM立体声信号。 瞬时相位角是在高电平下修正的正交相位角，在载波调制之前L-R信道中的高频减小。 高频L-R信道的增益可以仅与信号电平或电平和频率成比例地降低，或者通过对RF信号的RF滤波引入到L-R信号的高频中的百分比 调制载波。
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公开(公告)号：US4192968A
公开(公告)日：1980-03-11
申请号：US837258
申请日：1977-09-27
CPC分类号： H04H20/49
摘要： An improved AM stereo receiver for receiving broadcast signal having the form (1+L+R)cos(.omega..sub.c t+.phi.) where .phi. is arc tan(L-R)/(1+L+R). The sum signal (L+R) is demodulated in an envelope detector and coupled to a matrix. The uncorrected difference signal is demodulated in a synchronous detector, a corrector circuit derives the correction factor, and a divider circuit provides the corrected difference signal. During tuning, and until a PLL is locked on the carrier frequency, the receiver is locked into the monophonic mode and tuned on the monophonic signal. When the PLL locks, the difference signal is coupled through to the matrix for stereophonic mode operation.
摘要翻译： 一种改进的AM立体声接收机，用于接收具有形式（1 + L + R）cos（ω-ct + phi）的广播信号，其中phi为弧度（L-R）/（1 + L + R））。 和信号（L + R）在包络检测器中解调并耦合到矩阵。 未校正的差分信号在同步检波器中被解调，校正电路导出校正因子，并且分频器电路提供校正的差分信号。 在调谐期间，直到PLL被锁定在载波频率上，接收机被锁定在单声道模式中并在单声道信号上进行调谐。 当PLL锁定时，差分信号被耦合到用于立体声模式操作的矩阵。
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公开(公告)号：US4164623A
公开(公告)日：1979-08-14
申请号：US852272
申请日：1977-11-17
CPC分类号： H04H20/49
摘要： An AM receiver for receiving a compatible stereo signal and requiring a dynamic correction factor prevents the introduction of a false phase reference signal by limiting and filtering the signal going into the oscillator of the PLL which provides the correction reference signal.
摘要翻译： 用于接收兼容的立体声信号并需要动态校正因子的AM接收机通过限制和滤波进入提供校正参考信号的PLL的振荡器的信号来防止引入伪相位参考信号。
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公开(公告)号：US4371747A
公开(公告)日：1983-02-01
申请号：US133189
申请日：1980-03-24
申请人： Francis H. Hilbert
发明人： Francis H. Hilbert
IPC分类号： H04H20/88 , H01L31/112 , H04H1/00 , H04H20/49 , H04H5/00
CPC分类号： H04H20/49 , H01L31/1123
摘要： A decoder for use with a compatible AM stereophonic signal utilizes a amplifier and a feedback loop from the amplifier output to control the output of a multiplier circuit which is one input to the amplifier. The amplifier output is thus forced to become the required correction factor used in restoring the stereo program signals.
摘要翻译： 与兼容AM立体声信号一起使用的解码器利用来自放大器输出的放大器和反馈回路来控制作为放大器的一个输入的乘法器电路的输出。 因此，放大器输出被迫变成用于恢复立体声节目信号所需的校正因子。
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