JPH1041981A - Base band signal transmission reception method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To attain transmission reception in a state of reducing crosstalk noise by sending a base band signal modulated by a specific pseudo random code onto a transmission line, demodulating the base band signal, receiving and identifying the demodulated signal while being limited to a base band frequency band. SOLUTION: A clock signal of a same period as a bit period T of a binary base band signal is selected to be a multiple of 1/N (N is an integer being 2 or over) at a multiplier 204 in a transmitter and a pseudo random code is generated from a code generator 203 by using the clock signal whose period from the multiplier 204 is T/N. Then a base band signal to either of two adjacent transmission lines is modulated by the pseudo random code and the modulated signal is sent. On the other hand, the modulated base band signal from the transmission line is demodulated by a pseudo random code generated in a receiver and the demodulated signal is received while its frequency is limited to a base band frequency band and the logic is identified.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a base station which receives a baseband signal transmitted from a transmitting apparatus on two or more transmission lines in a parallel state, the baseband signal being restricted to a baseband frequency band by a receiving apparatus. In addition, the present invention relates to a method of transmitting and receiving a baseband signal at the time of identification. In particular, in each transmission path, wired baseband transmission is performed in a state where crosstalk noise between mutually adjacent transmission paths is reduced. And a method of transmitting and receiving a baseband signal.

[0002]

2. Description of the Related Art Conventionally, in various communication devices in general, radiated crosstalk noise from a transmission signal itself is suppressed as much as possible, while the influence of radiated crosstalk noise from an adjacent other transmission signal is suppressed to within an allowable range. Attempts to secure an error rate, achieve high-density mounting, and reduce power consumption have been made. However, as for crosstalk noise reduction technology, for example, a “practical noise reduction technique” (March 18, 1986) (stock)
Published by Japan Technology Economic Center, pp. 159-163) and "Transistor Technology Special No. 22" (August 1, 1993)
On the other hand, those described in CQ Publishing Co., Ltd., pages 84-86) and JP-A-4-20019 are known.

[0003] Here, the "actual noise reduction technique",
FIG. 6 shows a method of reducing crosstalk noise by “Transistor Technology SPECIAL No. 22”. As shown in the drawing, transmission lines 111 to 115 are arranged in parallel between the transmission device and the reception device, and the damping resistors 101 to 105 and the ferrite beads 106 to 105 correspond to these transmission lines 111 to 115, respectively.
110 are provided. Here, as a representative, for example, focusing on the transmission line 111, a damping resistor 101 is inserted in series with the transmission line 111 in order to match the output impedance of the transmission element in the transmission device with the characteristic impedance of the transmission line 111 itself. But,
As a result, generation of unnecessary reflected waves on the transmission path 111 can be reduced / suppressed, and the transmission power of the transmission signal can be reduced. Further, when the ferrite beads 106 are inserted in series in the transmission line 111 and a signal from the transmission device is transmitted on the transmission line 111, unnecessary high-frequency components are cut off, thereby causing radiation crosstalk to the adjacent transmission line 112 and the like. The noise has been reduced.

On the other hand, in the case of Japanese Patent Laid-Open No. 4-20019, a signal having a polarity opposite to that of a signal on the pattern wiring flows on a guard pattern arranged in parallel with each pattern wiring. As a result, the radiation crosstalk noise to the adjacent pattern wiring is effectively canceled. In addition, to reduce radiated crosstalk noise,
When mounting wiring, radiated crosstalk may be caused by wiring each transmission line as the distance between adjacent transmission lines is large, or by wiring transmission lines to minimize the transmission distance, or by providing a shield line between the wiring lines. The noise is suppressed within an allowable range.

[0005]

As described above, in the conventional wired baseband transmission interface, the radiated crosstalk noise from each transmission line and the influence of the radiated crosstalk noise from the adjacent transmission line are within an allowable range. Although the required error rate in the allowable section is ensured by the suppression, the radiated crosstalk noise from the adjacent transmission line has the same frequency band as the frequency band of the transmission signal. Noise power has been cited as a main factor in transmission waveform deterioration. For this reason, as the transmission speed of the interface circuit group increases, it is inevitable that radiation crosstalk noise to other transmission lines will increase due to the high frequency component of high radiation efficiency in the transmission signal having a wide band. That is the fact. Even if the transmission speed is increased, in order to reduce the radiated crosstalk noise within an allowable range, set the spacing between the wirings large, shorten the wiring length, or shield. Considerations in mounting design, such as providing a pattern between wirings, are required. However, even with such considerations, high-density wiring / mounting is becoming increasingly difficult.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a baseband between a transmitting device and a receiving device in a state where crosstalk noise between transmission lines adjacent to each other is reduced in each of transmission lines in a juxtaposed state. It is an object of the present invention to provide a baseband signal transmission / reception method in which signals can be transmitted / received.

[0007]

SUMMARY OF THE INVENTION The object of the present invention is to transmit a baseband signal from a transmitting device to each transmission line on at least one of two transmission lines adjacent to each other. Is transmitted from the transmitting apparatus in a state where the baseband signal is modulated by a pseudo-random code separately generated by a clock signal having a cycle of T / N, while the receiving apparatus transmits the modulated signal from the transmission path. The baseband signal in the state is demodulated by a pseudo-random code generated separately by a clock signal synchronized with the clock signal, and then received and identified as being restricted to the baseband frequency band. Or when the baseband signal is transmitted from the transmitting device on each transmission path, adjacent to each other. Of the two transmission paths in the state,
The baseband signal to at least one of the transmission paths is transmitted from the transmission apparatus as a state modulated by a clock signal having a cycle of T / N, while the reception apparatus transmits the modulation state from the transmission path. Is demodulated by a clock signal synchronized with the clock signal, received as a state limited to the baseband frequency band, and identified.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION For simplification of description, an embodiment of the present invention will be described with reference to FIGS. 1 to 5 assuming that a baseband signal is a binary baseband signal. First, a baseband signal transmission / reception system according to the present invention will be described. FIG. 1 shows a system configuration in one example. Incidentally, in each of FIGS. 4 and 5, which will be described later, starting with FIG. 1, each of the output circuit of the transmitting device, the input circuit of the receiving device, and the transmission line are assumed to be matched in advance and terminated. The circuit section is omitted, and the illustration of a synchronization circuit section 214 that is not directly related to the present invention for synchronizing the clocks between the transmission device and the reception device is simplified.

First, the system configuration as a premise is as follows.
This is because, as shown in FIG. 1, transmission lines 111 to 115 are arranged side by side between a transmission device and a reception device, and data 1 to data are transmitted from the transmission device to the transmission lines 111 to 115. 5 are transmitted as binary baseband signals, while the binary baseband signals from the respective transmission lines 111 to 115 are also transmitted through low-pass filters (LPFs) 209 to 213 in the receiving apparatus. By being restricted to the baseband frequency band,
The system is basically configured so that the logic can be identified by each of the classifiers 116 to 120 in a state where the unnecessary high-frequency component is removed.

[0010] The basic difference between the basic system configuration constructed as described above and that according to the present invention is that the bit period of the binary baseband signal in the transmitting apparatus according to the present invention is different. The clock signal having the same cycle as T has its cycle multiplied by 1 / N (N: generally an integer of 2 or more, the same applies hereinafter) by the multiplier 204, and the multiplier 204
, A pseudo random code is generated from the code generator 203 by the clock signal whose cycle is T / N,
While the baseband signal on at least one of the two transmission paths adjacent to each other is transmitted from the transmission apparatus as a state modulated by the pseudo-random code, the reception apparatus according to the present invention. Also, the binary baseband signal in the modulated state from the transmission path is demodulated by the pseudo-random code generated in the receiving apparatus, and then received as being restricted to the baseband frequency band. In addition, it is required that the logic be identified. In the receiving device, a clock signal that is phase-locked with the clock signal (before multiplication) in the transmitting device is obtained from the synchronization circuit unit 214, the period of which is made 1 / N times by the multiplier 208, and
A pseudo-random code is generated for demodulation from the code generator 207 by a clock signal having a cycle of T / N from the multiplier 208.

In this example, as shown in FIG.
Only the binary baseband signal on 114 is modulated by the pseudo random code in the transmitting device, and accordingly, in the receiving device, only the modulated binary baseband signal from each of transmission lines 112 and 114 is modulated. The case where demodulation is performed by a pseudo-random code is shown. That is, each of the data 1, data 3, and data 5 is transmitted as a binary baseband signal on the transmission lines 111, 113, and 115 while maintaining the frequency band of the signal itself.
After the frequency components of each of the low-pass filters 209, 211, and 213 are limited to the baseband frequency band, the logic is identified by each of the classifiers 116, 118, and 120. Generator 2
03 based on the pseudo-random code from
1 and 202 are transmitted on the transmission lines 112 and 114 as two-phase PSK phase-modulated states, and on the receiving apparatus side, before the frequency band limitation by the low-pass filters 210 and 212, the code generator 207 Are demodulated by the balanced modulators 205 and 206 into the original binary baseband signal based on the pseudo random code.
In other words, data 1 as a binary baseband signal
If the frequency band of each of the data 5 is 0 ≦ f ≦ fs, the frequency band when the binary baseband signal is transmitted as it is on the transmission lines 111, 113, 115 is also 0 ≦ f ≦ fs. , But the transmission paths 112, 1
14 when the binary baseband signal is transmitted as a two-phase PSK phase-modulated state, 0 ≦ f ≦ N ·
fs. As a result, the average power per unit frequency when the data 2 and the data 4 are transmitted on the transmission lines 112 and 114 are calculated assuming that the peak values of the data 1 to the data 5 are the same and the data 1 and the data 5 3,
Each of the data 5 is set to 1 / N as compared with that when the data 5 is transmitted on the transmission lines 111, 113 and 115.

Here, taking as an example the crosstalk noise between the transmission lines 112 and 113, it will be described in detail that the noise is sufficiently reduced as compared with the case of the basic system configuration. It is like. That is, FIG. 2 shows the frequency spectrum 301 when the data 3 is transmitted on the transmission path 113. The crosstalk noise spectrum 303 on the transmission path 112 due to this is shown in FIG.
3 is obtained as a product of the radiation crosstalk noise coefficient 302 and the frequency spectrum 301. As a result, the data 2 in the two-phase PSK phase modulated state is to be demodulated to the original data 2 by the balanced modulator 205 as a state in which crosstalk noise having the spectrum 303 is superimposed. The crosstalk noise is balanced modulator 205
Is obtained as crosstalk noise of the spectrum 304 having a frequency band of 0 ≦ f ≦ N · fs. In other words, the frequency band of the crosstalk noise is expanded N times, and the average power per unit frequency is obtained as 1 / N. Thereafter, in the low-pass filter 210, only the frequency band components of 0 ≦ f ≦ fs are passed, and unnecessary high-frequency components are removed.
In the classifier 117, the logic of the demodulated data 2 is identified as a state in which the crosstalk noise indicated as the spectrum 305 is superimposed. Obviously, the crosstalk noise in the basic system configuration is apparent. Spectrum 3
03, the crosstalk noise spectrum 3 to the classifier 117
05 is reduced to 1 / N.

On the other hand, FIG. 3 also shows a frequency spectrum 401 when the data 2 is transmitted on the transmission line 112 in a non-modulated state.
The crosstalk noise superimposed on the transmission path 113 as a product of the radiation crosstalk noise coefficient 402 between the signal 13 and the
It is what was shown as. By the way, data 2
Is actually two-phase PSK phase-modulated by a pseudo-random code. Therefore, if it is assumed that the peak value after modulation is the same as that before modulation, data 2 has a frequency band of 0 ≦ f ≦ N · fs, and transmitted as a spectrum 404 in which the average power per unit frequency is reduced to 1 / N compared to the frequency spectrum 401. As a result, the crosstalk noise superimposed on the transmission path 113 from the transmission path 112 as the product of the spectrum 404 and the radiation crosstalk noise coefficient 402 is the spectrum 40
5 is obtained. Thereafter, in the low-pass filter 211, only the frequency band component of 0 ≦ f ≦ fs is passed. However, the cross-talk noise in the state reduced to 1 / N as shown by the spectrum 406 is eventually generated in the discriminator 118. As a superimposed state, the logic of the demodulated data 3 is identified.

As can be seen from the above description, the crosstalk noise is reduced in each of the transmission lines 112 and 113 in the adjacent state. Between transmission lines 113 and 114, transmission line 1
The same applies to each of the sections 14 and 115.
Incidentally, when the same pseudo-random code is generated from each of the code generators 203 and 207, when the data 2 and the data 4 are modulated and demodulated by a pseudo-random code having a small time correlation and shifted by one bit or more from each other. Is
Crosstalk noise between the transmission lines 112 and 114 can also be reduced. Further, the code generators 203 and 2
07, a plurality of types of pseudo-random codes are simultaneously generated, and even if the bit periods of the pseudo-random codes are the same, data 2 and data 4 are modulated and demodulated by different pseudo-random codes. In this case, crosstalk noise between the transmission lines 112 and 114 can be reduced.

FIG. 4 shows a system configuration of another example of the baseband signal transmission / reception system according to the present invention. 1 are denoted by the same reference numerals, but are substantially different from those shown in FIG. 1 in that code generators 203 and 207 are not required, and multipliers 204 and 208 are not required. By the multiplied clock signal from each,
Direct data 2 and data 4 are balanced modulators 201,
That is, modulation and demodulation are performed in 205, 202, and 206. In this example, both data 2 and data 4 are transmitted on the transmission line 11.
(N−1) · fs and (N + 1) · f
s is transmitted in a 2PSK phase-modulated state in the frequency band between the adjacent transmission lines 111, 113, and 113, even if the average power per unit frequency is larger than that shown in FIG. Frequency characteristics 0 ≦ f ≦ fs on 115
Since it is possible to provide a frequency band and a frequency bandwidth different from those described above, the system configuration can be simplified and crosstalk noise can be reduced. By the way, the multiplier 2
When a plurality of types of multiplied clock signals having different frequencies are simultaneously generated from each of the data lines 04 and 208, and data 2 and data 4 are modulated and demodulated by the different multiplied clock signals, respectively, Can be reduced.

Finally, FIG. 5 shows a system configuration of an example of a baseband signal transmission / reception system according to the present invention in which each of data 1 to data 5 can be arbitrarily modulated and demodulated under selection control from the outside. As shown in FIG.
15 balanced modulators for modulation and demodulation 601, 610, 20
1,205,602,611,202,206,60
3 and 612, and each of the balanced modulators is provided with the same pseudo-random code having a different phase or a different pseudo-random code from the code generators 203 and 207, respectively. , 614-6
18 and can be distributed. Whether the pseudo random code is distributed or not is determined by the gate control element 604.
Control signals 60 to 608 and 614 to 618, respectively.
9, 613 depends on how they are set from outside the transmitting / receiving apparatus. Such a situation is the same even when data 1 to data 5 can be directly modulated and demodulated by the multiplied clock signal. Transmission line 1
Data 1 to data 5 according to the mounting conditions of 11 to 115
Data 1 to data 5 can be arbitrarily modulated and demodulated, including the case where each is not modulated or demodulated at all.

[0017]

As described above, according to the first and second aspects, in each of the transmission lines in the juxtaposed state, the crosstalk noise between the transmission lines adjacent to each other is reduced. The baseband signal can be transmitted and received between the transmitting device and the receiving device.

[Brief description of the drawings]

FIG. 1 is a diagram showing a system configuration of an example of a baseband signal transmission / reception system according to the present invention;

FIG. 2 is a diagram for explaining that crosstalk noise can be reduced in transmission paths that are in a mutually adjacent state;

FIG. 3 is a diagram for explaining that crosstalk noise can be reduced on the other of the transmission lines that are also adjacent to each other.

FIG. 4 is a diagram showing a system configuration of another example of the baseband signal transmission / reception system according to the present invention;

FIG. 5 is a diagram showing a system configuration of an example of a baseband signal transmission / reception system according to the present invention, in which data can be arbitrarily modulated and demodulated under external selection control;

FIG. 6 is a diagram for explaining a crosstalk noise reduction method according to the related art.

[Explanation of symbols]

111 to 115: transmission line, 116 to 120: discriminator, 2
01, 202, 205, 206, 601-603, 61
0-612: balanced modulator, 209-213: low-pass filter, 203, 207: code generator, 204, 208
... Multiplier, 214 ... Synchronous circuit unit, 604-608, 61
4-618: gate control element

Claims (2)

[Claims] 1. A base station according to claim 1, wherein the bit period of the baseband signal is T, and the baseband signals transmitted from the transmitting device on two or more transmission paths in a parallel state are limited to the baseband frequency band by the receiving device. A method for transmitting and receiving a baseband signal when the baseband signal is received and identified as a state, wherein when a baseband signal is transmitted from a transmitting apparatus to each transmission path, two transmission paths that are adjacent to each other are transmitted. The baseband signal transmitted to at least one of the transmission paths is transmitted as a state modulated by a pseudo-random code generated separately by a clock signal having a cycle of T / N (N: generally an integer of 2 or more). On the other hand, at the receiving device, the baseband signal in the modulated state from the transmission path is transmitted from the device, and the baseband signal is synchronized with the clock signal. A baseband signal transmission / reception method in which after being demodulated by a pseudo-random code separately generated by a lock signal, the baseband signal is received in a state limited to a baseband frequency band and then identified. 2. A base station apparatus according to claim 1, wherein the bit period of the baseband signal is T, and the baseband signals transmitted from the transmitting apparatus to two or more transmission paths in a parallel state are limited to the baseband frequency band by the receiving apparatus. A method for transmitting and receiving a baseband signal when the baseband signal is received and identified as a state, wherein when a baseband signal is transmitted from a transmitting apparatus to each transmission path, two transmission paths that are adjacent to each other are transmitted. The baseband signal to at least one of the transmission paths is transmitted from the transmitting apparatus as a state modulated by a clock signal having a cycle of T / N (N: generally an integer of 2 or more), while the receiving apparatus Then, the baseband signal in the modulated state from the transmission path is
A baseband signal transmitting and receiving method, wherein the baseband signal is demodulated by a clock signal synchronized with the clock signal, then received in a state limited to a baseband frequency band, and then identified.