JPS6019326A - Timing extracting system - Google Patents

Abstract

PURPOSE:To reduce the gain of an amplifier and to decrease the circuit scale by using an element having a positive resistance region and a negative resistance region, generating a signal close to an impulse signal at the leading/trailing of a main signal and extracting a timing component from the signal through the generation. CONSTITUTION:An Ezaki diode 4 has a negative resistance region in succession to the positive resistance region as shown in Fig. In inputting a signal of 0, 0 CMI code rule as shown in Fig. B, a current output having a waveform close to that of an impulse signal at the leading/trailing of the signal by the CMI code rule is obtained as the output as shown in Fig. C. The same shape of voltage waveform is obtained from this output by an operational amplifier 5. Since this voltage waveform includes the frequency component of 0-infinity , a 2fo component (where; fo is a repetitive frequency of the main signal) is extracted by using a BPF6 passing through the frequency of 2fo. In this case, since the output pulse is generated twice as much as that using a conventional differential circuit, the extracted 2fo component is increased.

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Technical field of the invention The present invention is applicable to a digital repeater that performs requiming, when extracting a frequency 2fo component that is twice as high as that of a digital repeater. This article relates to a timing extraction method that can be made smaller.

(b) Conventional technology and problems In a digital repeater that performs retiming, the main signal is based on the 1B2B code rule I CM I (Code marki).
version) + DM I (different
Conventionally, there are two methods for extracting the 2FO component, which is twice the repetition frequency fO of the main signal, from a signal such as tia7 markinversion), and a method using a slice amplifier and a method using a difference circuit. The sliced waveform is the pulse waveform of the main signal, and the latter outputs a signal close to the impulse O, but since this signal is output at either the rising or falling point of the main signal, it is difficult to use tank circuits, etc. The level at which the 2fo component is extracted is low. Special 1
As in Kool J, the apparent repetition frequency is f o
/ In the case of 2, the extraction level is even lower. Therefore, the gain of the amplifier for amplifying the extracted fc2fo signal must be set to a large value, which has the disadvantage of increasing the circuit scale.

tc) Purpose of the Invention The purpose of the present invention is to solve the above-mentioned drawbacks, especially to
In the B2B sign rule signal, the repetition frequency fo of the main A sign is
In the case of extracting a 2io component with a frequency twice that of the 2io component, the present invention aims to provide a timing extraction method that can reduce the original gain of an amplifier that amplifies the 2fo component and can reduce the circuit scale.

(d) Structure of the Invention In order to achieve the above object, the present invention uses an element having a positive resistance region and a negative resistance region to generate a signal close to the rising and falling points of the main signal [the iron impulse]. The present invention is characterized in that a timing component is extracted from a signal close to this impulse.

(e) Examples of the invention An embodiment of the present invention will be described below with reference to the drawings.

Fig. 1 is a block diagram of a digital repeater that performs signal timing according to an embodiment of the present invention, Fig. 2 is a signal waveform diagram expressed using the CMI code rule, and Fig. 3 is a diagram of the Ezaki diode f of Fig. 1.
This characteristic diagram shows the output current waveform when a signal with the CMI sign rule is input. (A) shows the voltage/current characteristics of the Ezaki diode, B) shows the signal with the CMI sign rule, and (c) shows the output current waveform. show.

In the figure, 1 is an equalization amplifier, 2 is an identification regenerator, 3 is a timing circuit, 4 is an Ezaki diode, 5 is an operational amplifier, and 6 is a 2
A bandpass filter (hereinafter referred to as BPF) that passes fo.

The configuration of a digital repeater that performs retiming generally includes an equalization amplifier 1, an identification regenerator 2, and a timing circuit 3, as shown in FIG.

The present invention deals with the case where the timing circuit 3 extracts a frequency 2fo that is twice the repetition frequency fo of the main signal. Here, an example in which the main signal follows the CMI code rule Q as shown in FIG. 2 will be explained.

The voltage/current characteristics of the Ezaki diode 4 in Fig. 1 are as follows.
As shown in Figure (A), there is a negative resistance area following the positive resistance area. The input of this Ezaki diode 4 is shown in Figure 3 (B
) When a signal with a CMI sign rule of 0,0 as shown in Ic is input, the output [This (is a CMI as shown in Figure 3)
A current output with a waveform close to an impulse can be obtained by the rise and fall of the signal according to the sign rule. This output is connected to the operational amplifier 5 to
If voltage conversion is performed, a voltage waveform similar to the impulse as shown in FIG. 3 (cl) can be obtained. This voltage waveform is close to an impulse and contains frequency components from 0 to oo, so it is 2f.

If you use BPF6 which passes the frequency of 2f, it is easy.

components can be extracted. Note that this voltage with a waveform close to an impulse is generated at the rise or fall of the main signal, so the output pulse is twice that of a conventional differential circuit that generates a voltage with a waveform close to an impulse at the rise or fall of the main signal. Therefore, the 2fo component to be extracted becomes large.

0 in Figure 3 continues (1/2 f in the case of CMI code)
Since output pulses are output with a period of o, C2f
Although it contains a large amount of O component, even in the case of the most continuous 2fo component, t2. in FIG. 3(c). The extraction level only drops by 6 db due to the absence of the output pulse at time t4. Therefore, the amplifier 3 which amplifies this output pulse
In the figure, the amplifier of the operational amplifier 5) contains components uniformly compared to the conventional method, so it is possible to extract the timing of a considerably wider range of frequencies than the main signal. It can also be used as a timing extraction circuit.

(fJ Effects of the Invention As explained in detail above, according to the present invention, the main signal is a signal on the IB2BB2 side, which is 2 times the repetition frequency fO of the main signal.
When extracting the frequency 2fol component, this 2
This has the effect of reducing the gain of the amplifier that amplifies the fo component and reducing the circuit scale.

[Brief explanation of drawings]

FIG. 1 is a block diagram of a digital repeater that performs glue timing according to an embodiment of the present invention! , Fig. 2 is a signal waveform diagram expressed using the CMI sign rule, and Fig. 3 is a characteristic showing the output current waveform when inputting a signal with the rule of CM I <e''' of the Ezaki diode in Fig. 1. In the figure, 1 is an equalization amplifier, 2 is an identification regenerator, 3 is a timing circuit, 4 is an analogue amplifier, 5 is an operational amplifier, and 6 is a bandpass P-wave device.

Claims (1)

[Claims] A digital repeater that performs retiming uses an element with a positive resistance region and a negative resistance region to generate a signal close to an impulse at the rising and falling points of the main signal. A timing extraction method characterized in that it extracts components.