摘要:
A receiver that easily receives signals from transmission channels having long cable lengths is presented. The receiver includes an analog pre-filter that removes distortions and intersymbol interference from a predetermined transmission channel. The analog pre-filter is coupled with a digital receiver that provides digital equalization. The combination of analog equalization with digital equalization allows for simplified digital equalization while retaining the versatility of digital signal processing.
摘要:
Analog echo-cancelling circuitry (611 and 627) operates on an input analog signal that includes an echo of an output signal, or on an analog signal generated from the input signal, to produce an analog signal with reduced echo. An analog-to-digital converter (210) converts the echo-reduced analog signal, or an analog signal generated therefrom, into a digital signal. Digital echo-cancelling circuitry (615 and 621) operates on the digital signal, or on a digital signal generated therefrom, to produce a digital signal with further reduced echo. An output decoder (605) decodes the echo-reduced digital signal, or a digital signal generated therefrom, into a stream of symbols. The echo-filtering characteristics of both echo-cancelling circuitries are typically adaptively adjusted during generation of the symbol stream. The analog echo-filtering characteristics may be adapted in response to information provided by operating on the echo-reduced digital signal or on a digital signal generated therefrom.
摘要:
A receiver system contains an analog pre-filter (207 or 619), an analog-to-digital converter (210), a digital equalizer (212), and a decoder (605) arranged sequentially for processing an input analog signal (yk). The pre-filter produces a filtered analog signal (Zs) with reduced intersymbol interference. The converter provides analog-to-digital signal conversion. Digital equalization circuitry in the equalizer operates according to a transfer frmnction c - 1 z + c 0 + ∑ M i = 1 c i z - i to produce an equalized digital signal (a'k) as a stream of equalized digital values. Coefficients c−1 and c0 are fixed. Each other coefficient ci is adaptively chosen. The decoder converts the equalized digital values, or intermediate values generated therefrom, into a stream of symbols. A receiver system may include two or more receivers each configured in the foregoing way with the digital equalization circuitry in each receiver operating according to a transfer function ∑ i = - N M c i z - i where at least coefficients c−1, c0, and c1 are non-zero.
摘要翻译:一个接收机系统包括一个模拟预滤波器(207或619),一个模数转换器(210),一个数字均衡器(212)和一个解码器(605),它们依次排列,用于处理输入的模拟信号(yk) 。 预滤波器产生具有减少的符号间干扰的滤波模拟信号(Zs)。 该转换器提供模数转换。 均衡器中的数字均衡电路根据传输速率c-1 z + c 0 +ΣM i = 1 ci z-i进行操作,以产生均衡数字信号(a'k)作为均衡数字值流 。 系数c-1和c0是固定的。 自适应地选择其他系数ci。 解码器将均衡的数字值或由其生成的中间值转换成符号流。 接收机系统可以包括两个或更多个接收机,每个接收机以前述方式配置,其中每个接收机中的数字均衡电路根据传递函数Σi = - NM ci z-i进行操作,其中至少系数c-1,c0, 而c1不为零。
摘要:
An analog equalizer (613 and 614) adaptively equalizes an input analog signal affected with intersymbol interference (“ISI”), or an intermediate analog signal generated therefrom, to produce a filtered partially equalized analog signal with reduced ISI. An analog-to-digital converter (210) converts the filtered analog signal, or an intermediate analog signal generated therefrom, into an initial digital signal. A digital equalizer (212) adaptively equalizes the initial digital signal, or an intermediate digital signal generated therefrom, to produce an equalized digital signal as a stream of equalized digital values with further reduced ISI. An output decoder (605) decodes the equalized digital values, or intermediate digital values generated therefrom, into a stream of symbols. Equalization control circuitry (213, 214, and 217) adjusts equalization filter characteristics of the equalizers such that adjustments of the filter characteristics of the analog equalizer depend adaptively on adaptive adjustments of the filter characteristics of the digital equalizer.
摘要:
A receiver system suitable for a local area network contains an analog pre-filter (207 or 619), an analog-to-digital converter (210), a digital equalizer (212), and a decoder (605). A symbol-information-carrying input analog signal (yk), or a first intermediate analog signal generated from the input analog signal, is filtered by filtering circuitry in the pre-filter to produce a filtered analog signal (Zs) with reduced intersymbol interference. The filtering circuitry operates according to a transfer function such as (b1s+1)/(a2s2+a1s+1) or (1−Vc)+VcPF(s) where Vc is adaptively varied. The analog-to-digital converter provides analog-to-digital signal conversion. The equalizer provides digital signal equalization to produce an equalized digital signal (a′k) as a stream of equalized digital values. The decoder converts the equalized digital values, or intermediate digital values generated from the equalized digital values, into a stream of symbols.
摘要翻译:适用于局域网的接收机系统包含模拟预滤波器(207或619),模拟 - 数字转换器(210),数字均衡器(212)和解码器(605)。 由输入的模拟信号产生的符号信息输入模拟信号(或从输入的模拟信号产生的第一中间模拟信号)由预滤波器中的滤波电路进行滤波,以产生经滤波的模拟信号 (Z s S)具有减少的符号间干扰。 滤波电路根据传递函数进行操作,例如(b 1> 1 + 1)/(a 2< 2> 2< 1 + 1)或(1-V C c)+ V C c C(s)其中V C c C被自适应地变化 。 模数转换器提供模数转换。 均衡器提供数字信号均衡以产生均衡的数字信号(一个“k”)作为均衡数字值的流。 解码器将均衡的数字值或从均衡的数字值生成的中间数字值转换成符号流。
摘要:
A receiver that easily receives signals from transmission channels having long cable lengths is presented. The receiver includes an analog pre-filter that removes distortions and intersymbol interference from a predetermined transmission channel. The analog pre-filter is coupled with a digital receiver that provides digital equalization. The combination of analog equalization with digital equalization allows for simplified digital equalization while retaining the versatility of digital signal processing.
摘要:
An analog equalizer (613 and 614) adaptively equalizes an input analog signal affected with intersymbol interference (“ISI”), or an intermediate analog signal generated therefrom, to produce a filtered partially equalized analog signal with reduced ISI. An analog-to-digital converter (210) converts the filtered analog signal, or an intermediate analog signal generated therefrom, into an initial digital signal. A digital equalizer (212) adaptively equalizes the initial digital signal, or an intermediate digital signal generated therefrom, to produce an equalized digital signal as a stream of equalized digital values with further reduced ISI. An output decoder (605) decodes the equalized digital values, or intermediate digital values generated therefrom, into a stream of symbols. Equalization control circuitry (213, 214, and 217) adjusts equalization filter characteristics of the equalizers such that adjustments of the filter characteristics of one of the equalizers depend adaptively on adaptive adjustments of the filter characteristics of the other equalizer.
摘要:
There is disclosed a transceiver for use in a high speed Ethernet local area network (LAN). The transceiver comprises: 1) front-end analog signal processing circuitry comprising: a) a line driver for transmitting an outgoing analog signal to an external cable; b) a DC offset correction circuit for reducing a DC component in an incoming analog signal; c) an echo canceller; d) an automatic gain control (AGC) circuit; and e) an adaptive analog equalization filter. The transceiver also comprises: 2) an analog-to-digital converter (ADC) for converting the analog filter incoming signal to a first incoming digital signal; and 3) digital signal processing circuitry comprising: a) a digital finite impulse response (FIR) filter; b) a digital echo cancellation circuit to produce a reduced-echo incoming digital signal; c) a digital automatic gain control (AGC) circuit; and d) a digital base line wander circuit.
摘要:
There is disclosed a transceiver for use in a high speed Ethernet local area network (LAN). The transceiver comprises: 1) front-end analog signal processing circuitry comprising: a) a line driver for transmitting an outgoing analog signal to an external cable; b) a DC offset correction circuit for reducing a DC component in an incoming analog signal; c) an echo canceller; d) an automatic gain control (AGC) circuit; and e) an adaptive analog equalization filter. The transceiver also comprises: 2) an analog-to-digital converter (ADC) for converting the analog filter incoming signal to a first incoming digital signal; and 3) digital signal processing circuitry comprising: a) a digital finite impulse response (FIR) filter; b) a digital echo cancellation circuit to produce a reduced-echo incoming digital signal; c) a digital automatic gain control (AGC) circuit; and d) a digital base line wander circuit.
摘要:
There is disclosed a mixed mode equalization system for use in a transceiver capable of operating in a high frequency Ethernet local area network (LAN). The mixed mode equalization system comprises: 1) an adaptive analog equalization filter for amplifying a first high frequency component of an incoming analog signal by a first adjustable gain factor to produce an analog filtered incoming signal; 2) an analog-to-digital converter (ADC) for converting the analog filter incoming signal to a first incoming digital signal; 3) a digital finite impulse response (FIR) filter for amplifying a second high frequency component of the first incoming digital signal factor to produce a digital filtered incoming signal; 4) a digital FIR controller for modifying at least one digital filter coefficient of the digital FIR filter according to a signal error associated with a digital output of the digital FIR filter; and 5) an analog equalization controller for modifying the first adjustable gain factor associated with the adaptive analog equalization filter according to a value of the at least one digital filter coefficient.