JPH0613249U - Signal receiver - Google Patents

Abstract

(57) [Abstract] [Purpose] To realize a signal receiving device having a simple structure, stable operation, a wide dynamic range, and high sensitivity. [Structure] A second amplifier AP2 that inputs a signal from the first amplifier AP1 and amplifies it, and a second amplifier A
A third amplifier AP3 having a gain different from that of P2
A peak hold circuit PH for holding the peak value of the signal from the first amplifier AP1 and a signal from the peak hold circuit PH with a predetermined reference level,
First amplifier CP2 and third amplifier AP3 that operate, a first comparator CP1, an equalizer IR that equalizes the signal from the third amplifier AP3, and a signal level from the second amplifier AP2. And a second comparator CP2 for comparing the first threshold value with the equalizer I
A third comparator CP3 that compares the signal from R with a second threshold value, and a threshold value control that controls each of the first and second threshold values based on the signal from the peak hold circuit PH. And means CNT.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a signal receiving device applied to a communication system for performing data transmission between a plurality of communication devices connected to a communication line, and more particularly to a dynamic range transmitted via the communication line. The present invention relates to a signal receiving device capable of receiving a wide range of signals with high sensitivity.

[0002]

[Prior art]

 When data transmission is performed using a serial transmission line, transmission is performed using communication frames. In this case, the signal level of the communication frame becomes a signal with a wide dynamic range depending on transmission conditions and the like.

Conventionally, as a device for receiving a signal having a wide dynamic range transmitted through such a communication line, a feedback amplifier is used as an amplifier or an AGC circuit for automatically changing a gain is provided. Was configured. Separately from this, a comparator for converting a received signal into a pulse signal is provided with an ATC circuit that automatically changes the threshold value according to the level of the received signal.

[0004]

[Problems to be solved by the device]

 However, according to the conventional device having such a configuration, there are various restrictions on the circuit design, such as the circuit configuration being complicated and the circuit being required to be prevented from oscillating, which makes the design difficult. There was a problem.

The present invention has been made in view of the above circumstances, and an object thereof is to provide a signal receiving device which has a simple structure, operates stably, has a wide dynamic range, and has high sensitivity. .

[0006]

Means for Solving the Problems The present invention that achieves such an object is a signal receiving device that receives a signal sent via a communication line and sends the signal to a higher-level device, which amplifies the received signal. And a gain of the second amplifier that inputs a signal from the first amplifier and amplifies it, and inputs a signal from the first amplifier and amplifies it. Is a third amplifier having a different gain, a peak hold circuit for holding the peak value of the signal from the first amplifier, a signal from this peak hold circuit is compared with a predetermined reference level, and the second amplifier And a third amplifier for operating one of the third and third amplifiers, an equalizer for equalizing a signal from the third amplifier, a signal level from the second amplifier, and a first threshold value. Second to compare A comparator, a third comparator for comparing the signal from the equalizer with a second threshold, and a signal from the peak hold circuit for determining the first and second thresholds. And a threshold control means for controlling the signal reception apparatus.

[0007]

[Action]

 The first amplifier, the second amplifier, and the second comparator constitute one signal amplification system, and the first amplifier, the third amplifier, the equalizer, and the third comparator are the other one. It constitutes the signal amplification system.

The first comparator selects one of the two amplification systems having the optimum amplification factor in accordance with the level of the received signal, and the threshold control means sets the second or third amplification system. The threshold value of the comparator is set to an optimum value according to the level of the received signal.

[0009]

Embodiments of the present invention will be described in detail below with reference to the drawings. FIG. 1 is a configuration block diagram showing an embodiment of the present invention. In the figure, BS is a communication line, to which a plurality of communication devices (not shown) are connected, and serial transmission communication using a communication frame is performed between these communication devices. ing.

AP1 is a first amplifier that receives and amplifies a signal sent via the communication line BS, and AP2 is a second amplifier that inputs the signal from the first amplifier AP1 and amplifies it. , AP3 is a third amplifier which inputs the signal from the first amplifier AP1 and amplifies it, and has a gain different from that of the second amplifier AP2.

PH is a peak hold circuit that holds the peak value of the signal from the first amplifier AP1, and is composed of, for example, a diode, a capacitor, and a buffer. C P1 is a first comparator, which compares the signal from the peak hold circuit PH with a predetermined reference level Vth1 and outputs a signal for operating one of the second amplifier AP2 and the third amplifier AP3. Output.

IR is an equalizer for equalizing the signal from the third amplifier AP3, CP2 is a second comparator, and compares the signal level from the second amplifier AP2 with the second threshold Vth 2. CP3 is a third comparator, which compares the signal from the equalizer IR with a third threshold Vth3. CNT is a threshold control means for controlling the second and third threshold values Vth2 and Vth3, respectively, based on the signal from the peak hold circuit PH. In this threshold control means CNT, two ATC (Automatic threshold control) amplifiers are used here.

The first amplifier AP1, the second amplifier AP2, and the second comparator CP2 constitute one amplification system that amplifies the received signal, and the first amplifier AP1, the third amplifier AP3, and the equalizer. The IR and the third comparator CP3 constitute another amplification system for amplifying the received signal, and the second and third comparators CP2 and CP3 discriminate by the corresponding threshold value. A pulse signal that changes to high / low is output.

The operation of the apparatus thus configured will be described below. FIG. 2 is a time chart showing the operation of signal reception. Here, V1 represents a signal waveform (communication frame signal) sent via the communication circuit BS, and as shown in the figure, the amplitude changes to both positive and negative polarities, and the magnitude of the amplitude changes. Well, it depends on the transmission conditions.

The first amplifier AP1 amplifies such a communication frame signal, applies its output to the second and third amplifiers AP2, AP3, and also applies it to the peak hold circuit PH. The peak hold circuit PH temporarily holds the maximum level of the communication frame signal output from the first amplifier AP1. The first comparator CP1 compares the maximum value level output from the peak hold circuit PH with a predetermined reference level Vth1 to operate one of the second amplifier AP2 and the third amplifier AP3. To output the signal.

That is, when the maximum value level is higher than the reference level Vth1, the second amplifier AP2 is turned on (operating state) and the third amplifier AP3 is turned off (non-operating state). Thereby, when the maximum value level is higher than the reference level Vth1, the amplified signal V2 is output from the second amplifier AP2 side. On the other hand, when the maximum value level is lower than the reference level Vth1, the third amplifier AP3 is turned on (operating state) and the second amplifier AP2 is turned off (non-operating state). Further, in the case of silence (when there is no received signal), the third amplifier AP3 having a large gain is in the ON state so that the frame can be received even if the frame of the next smaller level comes. Here, it is assumed that the gain G2 of the second amplifier AP2 and the gain G3 of the third amplifier AP3 have a relationship of G3> G2. Further, the two amplifiers AP2 and AP3 are not turned off or on at the same time.

Thus, when the maximum value level is higher than the reference level Vth1, the amplified signal V2 multiplied by the gain (G2) by the second amplifier AP2 is output, and when the maximum value level is lower than the reference level Vth1. , And outputs the amplified signal V3 multiplied by the gain (G 3) by the third amplifier AP3. In this way, the dynamic range of the receivable level is widened by switching between two amplifiers with different gains.

The threshold control means CNT inputs the maximum value level signal output from the peak hold circuit PH and is suitable for the output level signals V2 and V3 from the second and third amplifiers by the ATC function. Further, the threshold value Vth2 or Vth3 is set in the second comparator CP2 or the third comparator CP3, respectively. The second comparator CP2 compares the signal level from the amplifier AP2 with the second threshold value Vth2. The third comparator CP3 compares the signal from the equalizer IR with the third threshold value Vth3.

The threshold values set in the second and third comparators are set automatically by the ATC function, so that appropriate threshold values corresponding to various levels can be set automatically. The range of the receivable level is widened, and the S / N ratio of the comparator is increased to improve the sensitivity of the receiving device.

FIG. 3 is a connection diagram showing an example of the amplifier AP, the peak hold circuit PH, and the threshold value control means CNT. Here, the circuit considered so as not to be influenced by the ambient temperature is shown.

In this figure, a buffer amplifier AP is composed of a differential amplifier AP10 for amplifying a received signal and an emitter follower transistor Q1 which is an output means thereof, and a peak hold circuit PH includes a diode D1 and a capacitor C, and It is composed of an emitter follower transistor Q2. The threshold control means CNT is composed of a single-ended differential amplifier including transistors Q3 and Q4. Here, the base potential of the transistor Q4 is determined by the resistors R1, R2, the transistor Q5, and the diodes D2, D3. That is, the potential divided by the resistors R1 and R2 is buffered by the transistor Q5, and the potential of the emitter of the transistor Q5 is applied to the base of the transistor Q4 via the series circuit of the diodes D2 and D3. is there.

By making such a connection, the number of three PN junctions of the diodes D2 and D3 and the transistor Q5 is equal to that of the transistor Q1 in the amplifier AP, the diode D1 in the peak hold circuit, and the transistor Q2. Corresponding to the number of three PN junctions, the temperature changes at these junctions are canceled by the differential amplifiers Q3 and Q4, and the threshold values Vth2 and Vth3 given to the comparator have temperature dependence. It is devised so that it does not exist.

By configuring the amplifier AP, the peak hold circuit PH, and the threshold value control means CNT as described above, the received signal is accurately changed to high / low level without being affected by the ambient temperature and the like. It becomes possible to make it a pulse signal.

[0024]

[Effect of device]

 As described above in detail, according to the present invention, the system having the optimum amplification factor of the two signal amplification systems is selected according to the level of the received signal, and the threshold value of the comparator is selected. By setting the above, it is possible to realize a signal receiving device that has a simple structure, operates stably, has a wide dynamic range, and high sensitivity. Also, by using a threshold control circuit equipped with a temperature compensation circuit, a device that is not affected by the ambient temperature can also be realized.

[Brief description of drawings]

FIG. 1 is a configuration block diagram showing an embodiment of the present invention.

FIG. 2 is a time chart showing a signal receiving operation.

FIG. 3 is a connection diagram showing an example of an amplifier AP, a peak hold circuit PH, and a threshold value control means CNT.

[Explanation of symbols]

 BS communication line AP1 first amplifier AP2 second amplifier AP3 third amplifier PH peak hold circuit CP1 first comparator IR equalizer CP2 second comparator CP3 third comparator CNT threshold control means

Claims (2)

[Scope of utility model registration request] 1. A signal receiving device for receiving a signal sent via a communication line and sending the signal to a higher-order device, the first amplifier amplifying the received signal, and the signal from the first amplifier. A second amplifier for inputting and amplifying the signal, a third amplifier having a gain different from the gains of the second amplifier for inputting and amplifying the signal from the first amplifier, and a first amplifier A peak hold circuit for holding the peak value of the signal from the first amplifier, comparing the signal from the peak hold circuit with a predetermined reference level, and turning on one of the second amplifier and the third amplifier. 1 comparator, an equalizer for equalizing the signal from the third amplifier, a second comparator for comparing the signal level from the second amplifier with a first threshold value, and a signal from the equalizer Second A third comparator for comparing the threshold, based on a signal from the peak hold circuit, the first, the signal reception apparatus that includes a threshold value control means for controlling the second respective threshold. 2. The threshold control means is composed of a single-ended differential amplifier, a signal from a peak hold circuit is applied to one input end of this differential amplifier, and the temperature dependence is applied to the other input end. 2. The signal receiving device according to claim 1, wherein a signal with a signal is applied.