WO1993024997A1

WO1993024997A1 - Digital signal receiver

Info

Publication number: WO1993024997A1
Application number: PCT/JP1993/000682
Authority: WO
Inventors: Takeo Kaharu
Original assignee: Japan Aviation Electronics Industry Limited
Priority date: 1992-05-25
Filing date: 1993-05-24
Publication date: 1993-12-09
Also published as: CA2113898A1; JPH05327433A

Abstract

In a digital signal receiver, an input optical signal SOP is converted to an electrical signal by a photodetector (14) of a receiving circuit R, is amplified by an amplifier (15) and is compared with a reference voltage by a comparator (16), which produces a signal Sd. This signal is supplied as a trigger signal to a re-triggerable monostable multivibrator (17) to produce a square wave signal Sdo having a predetermined width. The signal Sd from the circuit R is added to the signal Sdo from the multivibrator (17), and the resulting signal So is output from the receiver.

Description

Specification

Digital signal receiver

Technical field

The present invention relates to an optical or electric digital signal receiving apparatus, and more particularly to a method for reducing a rise / delay time from input of a received signal to generation of an output signal.

The conventional configuration will be described with reference to the signal waveforms of the respective units shown in FIG. 2 taking the optical signal transmitting and receiving devices shown in FIGS. 1A and 1B as examples. A digital signal input to the transmitter T shown in FIG. 1A (for example, a Munchister code as shown in row A of FIG. 2) S _di is a rising edge of the modulation circuit 11 or a certain time thereafter. It is modulated into a pulse signal S m (B in Fig. 2) generated at a later timing. The output S _m is input to the drive circuit 12, the output is supplied to the light emitting element 13, and the electric signal is the optical signal S. _It is converted to _P (B in Fig. 2) and incident on the transmission medium. This optical signal S. The receiving device in FIG. 2B receiving _P receives the signal S. _P is photoelectrically converted by the light receiving element 14, amplified by the amplifier circuit 15, compared with the reference voltage by the comparator 16, and the digital signal S _d (line C in FIG. 2) is reproduced. However, since this is just a timing signal, a monostable multi-signal that can normally re-trigger the signal S _{d in} order to reproduce the digital signal (Mnister code) S _d input to the transmitter T from now on Input as a trigger signal to vibrator (LS123, etc.) 17 to generate pulse signal _Sdo (D in Fig. 2) with a predetermined width.

Figure 3 shows the transmission and reception processes described above using timing charts of signals at each stage, including the delay time of each circuit block. In the figure, the input signal S _di is the optical signal S. The rise delay time for conversion to _P is calculated by the delay time from the light-receiving element 14 to the output S _d of the comparator 16 ₂ , the output power of the comparator S d, and the output of the multivibrator 17. S _d . Assuming that the delay time until is ₃ , the total delay time in this modulation and demodulation process is considered without including the delay of the transmission path. == \ + = 20 + 3

Thus, using the conventional receiver, the total delay time of transmission and reception is

, R = r 1 + τ ₂ + r ₃ , and for applications where the total transmission and reception delay time r is strict, it is necessary to make this value smaller.

An object of the present invention is to reduce a delay time of a signal receiving device.

Disclosure of the invention

According to the present invention, an OR gate is added to the conventional receiving apparatus, an OR of the output of the receiving circuit and the output of the monostable multivibrator is obtained, and the output of the OR gate is used as the output of the receiving apparatus. Things. In general, the OR gate has a shorter signal rise delay time than the monostable multivibrator, so the rise delay time of the receiver is reduced by that difference.

BRIEF DESCRIPTION OF THE FIGURES

Figure 1A is a block diagram of a conventional transmitter.

Figure 1B is a block diagram of a conventional receiver.

FIG. 2 is a waveform diagram of a main part of FIGS. 1A and 1B.

Fig. 3 shows the timing chart of the signals in Figs. 1A and 1B.

0

FIG. 4 is a block diagram of the receiver of the present invention.

Fig. 5 is a timing chart of the signals in Fig. 1A and Fig. 4.

BEST MODE FOR CARRYING OUT THE INVENTION

FIG. 4 is a circuit block diagram of an embodiment of the digital signal receiving apparatus according to the present invention, and FIG. 5 rows A to E show timing charts of signals in respective units. In this example, an optical signal receiving apparatus is used, and an optical signal S is transmitted from the transmitter in FIG. 1A. _P shall be received. The receiving circuit R has the same configuration as that shown in FIG. 1A. First, as an input signal S _di of the transmitter T of FIG. 1A, a pulse signal (such as a Munchister code) having a pulse width Tw shown in row A of FIG. 5 is input. Converted to a mining signal. The timing signal is applied to the light emitting element 13 to generate an optical signal S. _It is converted to _P (Fig. 5, line B) and incident on the transmission medium. Optical signal S from input signal S _di . _Let the delay time to _{P be} . This optical signal S. _P is incident on the light receiving element 1 4 in the receiver of FIG. 4, the output of the amplifier circuit 1 5 through the comparator 1 6, 2 value Di digital signal S _d is outputted from the receiving circuit R. Optical signal S. The delay time from _P to the receiving circuit output S d is defined as r ₂ without including the delay of the transmission line.

In the present invention, the receiving circuit output S _d is multiplied by the trigger input terminal of the monostable multivibrator 17 and the receiving circuit output S _d at the 0 org 18 input to the final OR gate 18. Piblator output S _d . (Fig. 5, line D) is added to the final output signal S. (Fig. 5, line E) Therefore, the rising edge of the output signal S is the two input signals S _d and S _d of OR gate 18. Ri determined by the earlier ones of, the gate delay becomes r _4. In general, the delay of orgate ₄ is smaller than the delay of monostable multivibrator 17 and 3; therefore, the total delay time of transmission and reception is て, て + r2 + r4, The delay time becomes smaller by ₃ -τ 4.

For example, when the analog one-shot multi-LS 123 is used as the multivibrator 17, the rise delay is 23 to 44 nsec. On the other hand, when the high-speed Oagate HD74 AC32 is used as the orgate 18, the gate delay is 5.5 to 8.5 nsec, so the delay can be reduced by 14.5 to 38.5 nsec. it can.

In the above description, the transmission signal of the transmission medium is an optical signal, but it is obvious that the present invention is not limited to the optical signal but may be an electrical signal.

As described above, according to the present invention, the output of the receiving circuit is set to the trigger signal. In a receiving device that generates a constant pulse in addition to a monostable multivibrator, the addition of OR gate 18 can reduce the overall delay time r of the received signal.

Claims

The scope of the claims

1. Receiving circuit means for receiving and detecting an optical or electrical digital signal Monostable multivibrator means for outputting a rectangular wave of a predetermined time width triggered by the leading edge of the rectangular wave output from the receiving circuit means A digital signal receiving device comprising: an OR gate that outputs a logical sum of an output of the monostable multivibrator and an output of the receiving circuit as an output of the receiving device.