JP3394279B2 - Data receiving device - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a data receiving device used for a digital car telephone or the like.

[0002]

2. Description of the Related Art FIG. 5 shows the configuration of a conventional data receiving apparatus. In FIG. 5, reference numeral 51 is an input end of the received signal. 52 is an oscillator that reproduces the carrier frequency of the received signal. Reference numeral 53 is a wave detector that obtains a baseband signal from the received signal, and is connected to the input terminal 51 and the oscillator 52. Reference numeral 54 denotes a clock regenerator that obtains a zero-cross signal from the baseband signal output from the detector 53 and creates a regenerated clock signal that represents the identification timing of the baseband signal based on the zero-cross signal, and is connected to the detector 53. . 5
Reference numeral 5 denotes a discriminator that discriminates received data from a regenerated clock signal that is generated by the clock regenerator 54 and represents a discrimination clock and a baseband signal from the detector 53. It is connected to the. 56 is an output end of the received data, and the discriminator 5
Connected to 5.

Next, the operation of the above conventional example will be described.
In FIG. 5, when a signal is received at the input terminal 51, a baseband signal is obtained by the wave detector 53 from the signal having the carrier frequency component of the received signal reproduced by the oscillator 52 and the received signal. If the transmitted data is random data, the polarity of the baseband signal changes on the average of 1/2 hour of the identification interval from the data identification time. Therefore, the clock regenerator 54 uses the detector 53. Detects the zero-cross signal output when the polarity of the baseband signal, which is the output signal of the, changes, and tracks the time difference between the zero-cross signal and the data identification timing to be 1/2 of the data identification interval. It is operated to generate data identification timing. The discriminator 55 discriminates whether the baseband signal is positive or negative at the discrimination timing created by the clock regenerator 54, and outputs received data from the output end 56 based on the result. Further, the oscillator 52 is used by using the error signal at the time of the discrimination by the discriminator 55.
Control the frequency of and make it follow the carrier frequency.

As described above, even the above conventional data receiving apparatus can decode received data without error.

[0005]

However, in the above-described conventional data receiving apparatus, the polarity of the baseband signal does not change at all depending on the pattern of the transmitted data, so that the output is made when the polarity of the baseband signal changes. There is a problem in that the identification time cannot be determined based on the zero-cross signal generated and the transmission speed cannot be synchronized with the transmitting station.

The present invention solves such a conventional problem, and provides an excellent data receiving apparatus capable of surely synchronizing transmission rates with a transmitting station for all data patterns. It is intended to be provided.

[0007]

In order to achieve the above-mentioned object, the present invention provides a first carrier frequency component of a received signal.
From the regenerated carrier signal and the carrier frequency of the regenerated carrier signal and the carrier frequency, the first regenerated carrier signal output from the oscillator and the first regenerated carrier signal received from the oscillator. A first detector that outputs a baseband signal of the above, a second detector that outputs a second baseband signal from the second reproduced carrier signal output from the oscillator and the received signal, and first and second
A clock regenerator which detects a zero-cross signal from all the baseband signals for all data patterns and creates a discrimination timing of the first baseband signal based on the detected zero cross signal, and a clock regenerator. A discriminator for discriminating the data transmitted from the reproduction clock signal representing the discrimination timing and the first baseband signal is provided.

[0008]

Therefore, according to the present invention, the zero-cross signal is generated for all the data patterns of QPSK to correct the identification timing for each symbol, thereby ensuring the synchronization of the transmission rate with the transmitting station. The received data can be reliably decoded.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows the configuration of a data receiving apparatus according to an embodiment of the present invention. In FIG. 1, reference numeral 1 is an input end of a received signal. Reference numeral 2 is an oscillator for reproducing a first reproduction carrier signal which is a carrier frequency component of the received signal and a second reproduction carrier signal which is a frequency component which is higher than the carrier frequency by a quarter of the symbol transmission rate of the transmission data. Three
Is a first detector that outputs a first base hand signal from the first reproduced carrier signal and the received signal output from the oscillator 2, and is connected to the input terminal 1 and the oscillator 2.
A second detector 4 outputs a second baseband signal from the second reproduced carrier signal output from the oscillator 2 and the received signal, and is connected to the input terminal 1 and the oscillator 2. The reference numeral 5 obtains a zero-cross signal from the first baseband signal output from the first detector 3, and the second detector 4
Is a clock regenerator that obtains a zero cross from the second baseband signal output from the first baseband signal, and creates a regenerated clock signal that represents the identification timing of the baseband signal based on those zero crossings. 4 is connected. Reference numeral 6 denotes a discriminator that discriminates between the reproduced clock signal representing the discrimination timing generated by the clock regenerator 5 and the data transmitted from the first baseband signal.
It is connected to the oscillator 2, the first detector 3, and the clock regenerator 5. An output terminal 7 of the received data is connected to the discriminator 6.

Next, the operation of the above embodiment will be described.
In the above-described embodiment, when a signal is first received at the input terminal 1, the first detector 3 makes a first detection from the first reproduction carrier signal and the reception signal having the carrier frequency component of the reception signal reproduced by the oscillator 2. To obtain the baseband signal of. FIG. 2 shows an example of changes in the first baseband signal at this time. In FIG. 2, the initial phase is π / 4 and the transmitted data is “0”.
If the phase change amount is π / 2 if it is “0”, the phase change amount is π if it is “01”, the phase change amount is 0 if it is “10”, and the phase change amount is −π / 2 if it is “11”. When the data is “00”, the polarity of the I signal of the first baseband signal is “11”, and when the data is “11”, the polarity of the Q signal of the first baseband signal is the identification interval from the data identification time. It changes to the time when 1/2 hour has passed, but "01", "1"
When it is 0 ", it is not so.

On the other hand, in the second detector 4, the second reproduced carrier signal and the received signal having a frequency component higher than the carrier frequency of the received signal reproduced by the oscillator 2 by 1/4 of the symbol transmission rate of the transmission data. A second baseband signal is obtained from and. FIG. 3 shows an example of changes in the second baseband signal at this time. In FIG. 3, the initial phase is π / 4, and if the transmitted data is “01”, the phase change amount is π / 2,
In the case of "11", the phase change amount is π, in the case of "00", the phase change amount is 0, and in the case of "10", the phase change amount is -π / 2. When the data is “01”, the polarity of the I signal of the second baseband signal is “10”, and when the data is “10”, the polarity of the Q signal of the second baseband signal is ½ of the discrimination interval from the discrimination time of the data. It changes with time, but not with "11" and "00".

The data transmitted in this way is "0".
If it is 0 "or" 11 ", the polarity of the first baseband signal changes from the identification time of the data to the time 1/2 hour after the identification interval, and if it is" 10 "or" 01 ", the second Since the polarity of the baseband signal changes from the identification time of the data to the time 1/2 hour after the identification interval, the clock regenerator 5 outputs the first baseband signal which is the output signal of the first detector 3. A zero-cross signal output when the polarity changes and a zero-cross signal output when the second baseband signal that is the output signal of the second detector 4 changes the polarity are detected to detect two types of signals. The tracking operation is performed so that the time difference between the zero-cross signal and the data identification timing is ½ of the data identification interval, and the data identification timing is reproduced. First in the identification timing The positive / negative of the first baseband signal output from the wave filter 3 is discriminated, and the received data is output from the output terminal 7 based on the result of the discrimination. The frequency of 2 is controlled to follow the carrier frequency.

Thus, according to the above embodiment, the QPS
Since the zero-cross signal is generated for all K data patterns and the identification timing is corrected for each symbol, the transmission rate can be reliably synchronized with the transmitting station, and the received data can be surely obtained. It has the advantage that it can be decoded into

FIG. 4 shows a second frequency component having a frequency component lower than the carrier frequency by 1/4 of the symbol transmission rate of transmission data.
It is an example of a change when the second baseband signal is obtained by using the reproduced carrier signal and the received signal of. Also at this time, as in the case of FIG. 3, when the transmission data is “01” and “10”, the polarity of the second baseband signal changes from the data identification time to the time 1/2 hour after the identification interval. Because
This is effective for acquiring synchronization of transmission speed.

Further, the first reproduced carrier signal is one of the carrier frequency of the received signal and 1 of the symbol transmission rate of the transmitted data.
The frequency component is / 8 higher, and the second reproduction carrier signal is 3 times the symbol transmission rate of transmission data from the carrier frequency.
When the frequency component is higher by / 8 or lower by ⅛, or when the first reproduced carrier signal is reduced by ⅛ of the symbol transmission rate, the second reproduced carrier signal is ⅜ of the symbol transmission rate. The same effect can be obtained by lowering it by 1/8 or raising it by 1/8.

[0016]

As is apparent from the above embodiment, the present invention differs from the first reproduction carrier signal and the carrier frequency, which are the carrier frequency components of the received signal, by a predetermined ratio with respect to the symbol transmission rate of the transmission data. An oscillator for reproducing the second reproduced carrier signal, a first detector for outputting a first baseband signal from the first reproduced carrier signal output from the oscillator and the received signal, and a second reproduced for the oscillator A second detector that outputs a second baseband signal from the carrier signal and the received signal, and a zero-cross signal for all data patterns from the first and second baseband signals is detected and used as a basis. A clock regenerator for generating the identification timing of the first baseband signal, a regenerated clock signal representing the identification timing produced by the clock regenerator, and the first baseband signal. Since a discriminator for discriminating the data transmitted from the received signal is provided, a zero-cross signal is generated for all the data patterns of QPSK to correct the discrimination timing for each symbol. In addition, the transmission rate can be reliably synchronized with the transmitting station, and the received data can be reliably decoded.

[Brief description of drawings]

FIG. 1 is a block diagram of a data receiving apparatus according to an embodiment of the present invention.

FIG. 2 is a correspondence diagram between transmission data and a first baseband signal.

FIG. 3 is a correspondence diagram between transmission data and a second baseband signal.

FIG. 4 is another correspondence diagram of the transmission data and the second baseband signal.

FIG. 5 is a block diagram of a conventional data receiving device.

[Explanation of symbols]

1 input end 2 oscillators 3 First detector 4 Second detector 5 clock regenerator 6 discriminator 7 Output end

─────────────────────────────────────────────────── ─── Continuation of front page (56) References JP-A-6-197138 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) H04L 27/00

Claims (7)

(57) [Claims] 1. A first carrier frequency component of a received signal
Of the reproduced carrier signal and carrier frequency, which reproduces a second reproduced carrier signal which differs from the symbol transmission rate of the transmission data by a predetermined ratio, and a first reproduced carrier signal output from the oscillator and a received signal. A first detector that outputs a first baseband signal, and a second detector that outputs a second reproduced carrier signal and a received signal output from the oscillator.
Second detector for outputting the baseband signal of the above and all data patterns from the first and second baseband signals.
A clock regenerator that detects a zero-cross signal with respect to the clock signal and creates an identification timing of the first baseband signal based on the detected zero-cross signal; a recovered clock signal that represents the identification timing created by the clock regenerator; And a discriminator that discriminates the data transmitted from the baseband signal. 2. The data receiving apparatus according to claim 1, wherein the second reproduced carrier signal is a frequency component which is higher than the carrier frequency by 1/4 of a symbol transmission rate of transmission data. 3. The data receiving apparatus according to claim 1, wherein the second reproduced carrier signal is a frequency component which is lower than the carrier frequency by 1/4 of a symbol transmission rate of transmission data. 4. The first reproduced carrier signal is 1/8 of the symbol transmission rate of transmission data from the carrier frequency of the reception signal.
Is a high frequency component, and the second reproduction carrier signal is
3 / the symbol transmission rate of the transmission data from the carrier frequency
The data receiving device according to claim 1, wherein the frequency component is 8 higher. 5. The first reproduced carrier signal is 1/8 of the symbol transmission rate of transmission data from the carrier frequency of the reception signal.
Is a high frequency component, and the second reproduction carrier signal is
1 / the symbol transmission rate of transmission data from carrier frequency
The data receiving apparatus according to claim 1, wherein the frequency component is 8 lower. 6. The first regenerated carrier signal is one-eighth of the symbol transmission rate of transmission data from the carrier frequency of the reception signal.
Is a low frequency component, and the second reproduction carrier signal is
3 / the symbol transmission rate of the transmission data from the carrier frequency
The data receiving apparatus according to claim 1, wherein the frequency component is 8 lower. 7. The first reproduced carrier signal is 1/8 of the symbol transmission rate of transmission data from the carrier frequency of the reception signal.
Is a low frequency component, and the second reproduction carrier signal is
1 / the symbol transmission rate of transmission data from carrier frequency
The data receiving device according to claim 1, wherein the frequency component is 8 higher.