JPH08186520A - Data transmitter/receiver - Google Patents

Abstract

PURPOSE: To provide a data transmitter/receiver with which the sensitivity of a received signal can be prevented from being degraded by the leak of a carrier wave from a transmitting part to a receiving part. CONSTITUTION: A transmitting part 19 digitally modulates a carrier wave S1 corresponding to transmitting data and further sends out a spread modulated spread spectrum signal (a). The receiving part extracts the frequency component of a partial band not including a frequency fc of the carrier wave S1 out of the frequency component of the received spread spectrum signal (a) by using a band passing means 21 and obtaines an intermediate signal (b). A detector 22 detects the intermediate signal (b) and obtaines a detecting signal (c). A clock reproducer 25 generates a regenerative clock and a decoder 23 outputs decoded data from the detecting signal (c) by using this regenerative clock. Thus, a frequency divider or a changeover switch for switching the frequency divider is unnecessitated and the carrier wave can be prevented from being leaked from the transmitting part to the receiving part.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a data transmission / reception apparatus for performing time division data transmission using the same frequency.

[0002]

2. Description of the Related Art FIG. 14 shows a conventional example of a data transmitter / receiver using a so-called TDD (Time Division Duplex) communication system, which transmits data in a time division manner using the same frequency. In FIG. 14, 1 is an antenna, 2 is a transmission / reception changeover switch that is switched between transmission and reception, 3 is a local oscillator, 101 is a transmission unit, and 102 is a reception unit. Further, in the transmitter 101, 160 is a modulator, 4 is a carrier generator, 5 is a first mixer, 6 is a bandpass filter, 7 is a high frequency amplifier, and 8 is a bandpass filter in the receiver 102. Is a high frequency amplifier, 10 is a second mixer, 121
Is a band pass filter, 122 is an amplifier, and 123 is a demodulation circuit.

First, the operation of the transmission unit 101 during transmission will be described.
I do. Frequency f output from carrier wave generator 4_cTransport of
The wave S1 is modulated by the transmission data in the modulator 160.
Intermediate frequency f_c As a modulated signal of
Is output. This modulated signal is input to the first mixer 5.
Local oscillator signal output from the local oscillator 3 (frequency
f _a) Is mixed and frequency converted. Output signal of mixer 5
Transmission / reception frequency f0 (f0 = f_a+ F_c ) Signal
It passes through the band pass filter 6 and is amplified by the high frequency amplifier 7.
And the transmission / reception changeover switch 2 connected to the transmitter side.
And is radiated into space via the antenna 1.

Next, the operation of the receiving section 102 during reception will be described. The signal received by the antenna 1 is sent to the band-pass filter 8 via the transmission / reception changeover switch 2 connected to the receiving side, and the predetermined frequency band (center frequency f0)
Signal is input to the high frequency amplifier 9 and amplified. The signal amplified by the high frequency amplifier 9 is mixed with the output signal (frequency f _a ) of the local oscillator 3 by the second mixer 10 and further converted into a signal having the intermediate frequency f _c as the center frequency.
This signal is input to the bandpass filter 121, and a reception signal in a predetermined band (hereinafter, referred to as an intermediate signal S2) having the intermediate frequency f _c as a center frequency passes through the bandpass filter 121. The intermediate signal S2 that has passed through the bandpass filter 121 is further amplified by the amplifier 122 and then demodulated by the demodulation circuit 123.

Since it takes time to start up the carrier wave generator 4 described above, it is necessary to operate the carrier wave generator 4 at the time of reception when the switching time between transmission and reception is short. However, the intermediate frequency f output from the carrier wave generator 4
_Since the level of the carrier wave S1 of _c is much larger than the level of the intermediate signal S2 in the receiving unit 102, if the carrier wave generator 4 is operating during reception, the carrier wave S1 leaking from the carrier wave generator 4 will be received. It is possible that the received signal sensitivity is deteriorated by jumping in, passing through the band pass filter 121, and interfering with the intermediate signal S2 in the amplifier 122.

As a method of solving such a problem, the oscillation frequency of the carrier wave generator 4 is set to a frequency higher than the intermediate frequency f _c , and the output of the frequency divider is divided, and the operation of the divider is stopped at the time of reception. There is a method in which a switch for performing this is provided between the carrier wave generator 4 and the modulator 160 so that the carrier wave of the frequency f _c is not generated from the transmission unit 101 during reception (for example, Japanese Patent Laid-Open No. 4-240924).

[0007]

However, the conventional method as described above requires a new frequency divider and a switch, which is disadvantageous in terms of cost and circuit scale. Further, there is a problem that it becomes difficult to realize as the intermediate frequency f _c becomes higher.

In consideration of the above problems of the conventional data transmitting / receiving apparatus, the present invention does not require a frequency divider or a switch for switching the operation of the frequency divider, and the carrier leaks from the transmitter to the receiver. An object of the present invention is to provide a data transmission / reception device capable of eliminating deterioration of received signal sensitivity.

[0009]

SUMMARY OF THE INVENTION The present invention is a data transmission / reception apparatus for transmitting / receiving data in a time division manner using the same frequency, and a carrier wave generator for outputting a carrier wave and an output from the carrier wave generator. A transmitter having a modulator that outputs a modulated signal obtained by digitally modulating a carrier wave using transmission data, and a frequency band of a partial band that does not include the frequency of the carrier wave among the frequency components of the received modulated signal. A data transmission / reception apparatus comprising: at least one bandpass means to be taken out, at least one wave detector for detecting an output signal of the bandpass means, and a receiver having a decoder for decoding the detected signal.

[0010]

According to the present invention, in the receiving section, only the frequency component of the partial band which does not include the frequency of the carrier wave is extracted from the frequency components of the modulated signal received by the band pass means, and the detector detects that band pass means. Since the output signal is detected, the reception quality does not deteriorate due to the carrier wave leaking from the transmitter to the receiver.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the drawings showing its embodiments.

FIG. 1 is a block diagram of a data transmitting / receiving apparatus according to a first embodiment of the present invention. In FIG. 1, 1
Is an antenna, 2 is a transmission / reception switch for switching between transmission and reception, 19 is a transmission unit, and 20 is a reception unit. In the transmitter 19, 16 is a modulator and 4 is a carrier generator. Further, in the receiving section 20, 21 is a bandpass means, 30 is an amplifier, 22 is a detector, 25 is a clock regenerator, and 23 is a decoder. FIG. 2 is a schematic diagram showing the relationship between the spectrum and the pass band, which shows the difference between the intermediate signal of the present embodiment and the intermediate signal of the receiving section described in the item “Prior Art”. FIG. 3 is a block diagram showing a configuration example of the modulator 16, where 11 is a differential encoder, 12 is a phase modulator, 13 is a spread modulation signal generator, 14 is a spread modulation multiplier, and 15 is a clock. It is a generator. FIG. 4 is a block diagram showing a configuration example of the detector 22, and 221 is a symbol delay unit and 222.
Is a multiplier and 223 is a low-pass filter. Also in FIG.
6 is a signal waveform diagram (a baseband waveform is shown for convenience) of each part of the apparatus of FIG. 1, and FIG. 6 is a block diagram showing a configuration example of the bandpass means 21.

Next, the operation of the data transmitting / receiving apparatus of the first embodiment will be described with reference to the drawings.

First, the operation during transmission will be described. As shown in FIG. 3, the data d, which is a bit string, is taken in by the modulator 16 in synchronization with the symbol clock CK, differentially encoded by the differential encoder 11, and then by the phase modulator 12.
The carrier wave S1 of the frequency f _c output from the carrier wave generator 4 is modulated to obtain the primary modulation signal p which is a two-phase phase modulated wave of the intermediate frequency f _c and the symbol period T. The primary modulation method is
For example, (differential) phase modulation such as 2, 4, or 8 phase is used. The spread modulation signal generator 13 uses the symbol clock CK.
In synchronism with, a spread modulation signal q having the same period as this is generated. The spread modulation signal q is a pseudo random pulse waveform having a constant amplitude generated by the pseudo random sequence. The spread modulation multiplier 14 multiplies the primary modulation signal p and the spread modulation signal q to obtain a spread spectrum signal a. Hereinafter, the operation up to this point will be described in more detail, taking the case where the primary modulation method is two-phase differential phase modulation as an example.

In the transmission device 19, the m-th transmission data d _m (in the case of ± 1, binary) is taken in in synchronization with the symbol clock CK of the period T, and differentially encoded by the differential encoder 11. Then, it is modulated by the phase modulator 12, and as its output, a primary modulation signal p which is a two-phase phase modulated wave of the symbol period T is obtained. The spread modulation signal generator 13 generates a spread modulation signal q having the same period as that of the symbol clock CK in synchronization with the symbol clock CK. The spread modulation signal q is, for example, a pseudo random pulse waveform with a constant amplitude generated by a pseudo random sequence. The spread modulation multiplier 14 multiplies the primary modulation signal p and the spread modulation signal q to obtain a spread spectrum signal a.

Now, the data after the differential encoding is represented by δ _m (±
If it is 1 or 2),

[0017]

## EQU1 ## It can be expressed as d _m = δ _m × δ _{m -1} . Therefore, if the frequency of the output carrier wave of the carrier wave generator 4 for transmission is f _c and Re [...] Is the real part, the spread spectrum signal a to be transmitted is expressed by the following equation.

[0018]

In Equation 2] a (t) = Re [δ m · q (t) · expj (2πf c t)] FIG. 5 (a), the primary modulation signal p, spreading modulation signal q, and spread spectrum signal a time The waveform is shown. However, for the primary modulation signal p and the spread spectrum signal a, baseband waveforms are shown for convenience. The spread spectrum signal a is radiated into space via the transmission / reception changeover switch 2 and the antenna 1 which are connected to the transmission section side.

Next, the operation at the time of reception will be described. Receiving
In the section 20, first, the spectrum spread received by the antenna 1 is spread.
The scattered signal a is band-limited by the band-passing means 21, and the center frequency is
Number f _cThe signal in the partial band that does not include
Let it be signal b.

FIG. 2 is a schematic diagram of a spectrum showing the difference between the intermediate signal b of this embodiment and the intermediate signal S2 in the receiving section of the conventional data transmitter / receiver. The intermediate signal b of this embodiment is a signal that has passed the band B1 or the band B2 of FIG. That is, the difference between the intermediate signal S2 in the receiving unit of the conventional example and the intermediate signal b in the receiving unit of the present embodiment is that the band of the intermediate signal S2 of the conventional example includes the frequency f _{c of the} carrier S1. On the other hand, the intermediate signal b of this embodiment
The band is a partial band of the received spread spectrum signal a, and the carrier frequency f _c of the carrier generator 4 is not included in the band. Therefore, even if the carrier wave S1 (frequency f _c ) output from the carrier wave generator 4 leaks from the transmitter 19 to the receiver 20,
The intermediate signal b in this embodiment is not affected by it.

After that, the intermediate signal b is amplified by the amplifier 30 and then input to the detector 22 and detected by the detector 22 to obtain a detected signal c. As the detector 22, for example, a delay detector 22 as shown in FIG. 4 is used.

FIG. 5B is a waveform diagram showing an example of the signal waveform of each part of the receiver 20. The baseband waveform of the spread spectrum signal a is
If the phases of the primary modulation signals are equal, they have the same shape,
When the phase of the primary modulation signal is opposite, it has a shape in which positive and negative are inverted. The intermediate signal b, which is the output of the bandpass means 21, is

[0023]

Equation 3] b (t) = Re [δ m · q '(t) · expj (2πf c t)] and expressed (δ _m = ± 1). The baseband waveform of the intermediate signal b is subjected to band limitation by the bandpass means 21 and has a waveform considerably different from the shape of the spread spectrum signal a (that is, q representing the complex envelope in (Equation 2)). In (equation 3), it is replaced with q ′ in the case of being band-limited), and in each symbol section, when the phases of the primary modulation signals are the same, they have almost the same shape, and When the phases are opposite to each other, the positive and negative polarities are inverted (as can be seen from (Equation 3), the positive and negative polarities of the waveform of b are inverted depending on the sign of δ _m ). Strictly speaking, in the vicinity of the boundary with the adjacent symbol, the shape will not be exactly the same due to the influence of the adjacent symbol, and intersymbol interference will occur, but the band of the intermediate signal is compared with the symbol repetition frequency. If it is made large, the intersymbol interference is small, so that it does not become a problem.

Next, in the delay detector 22 shown in FIG. 4, first, the symbol delay device 221 delays the intermediate signal b by the symbol period T to obtain the delayed intermediate signal b _d .
It is noted that the spread modulation signal q has a repetitive waveform of the period T, and that q ′ also has a repetitive waveform of the period T approximately.

[0025]

Equation 4] _{b d (t) = b (} t-T) = Re [δ m-1 · q '(t) · expj (2πf c t) · expj (-2πf
_c T)]. now,

[0026]

Equation 5] expj to satisfy (-2πf _c T) = 1, or precisely define the T, or by adjusting the phase of the output signal of the symbol delay unit 221, eventually delayed intermediate signal b _d is ,

[0027]

## EQU00006 ## b _d (t) = Re [δ _m-1 q '(t) exp j (2πf _c t)]. Of the output of the multiplier 222, the low-pass frequency component extracted by the low-pass filter 223, that is, the detection signal c, is a harmonic component expj ( By excluding the term of the component of 4πf _c t) and using (Equation 1),

[0028]

## EQU7 ## c (t) = δ _m · δ _m-1 {Re [q '(t)]} ² = d _m {Re
[q '(t)]} ² is obtained. From (Equation 7), it can be seen that the data is decoded by determining the polarity of the detection signal c.

FIG. 5B schematically shows the state of this detection process. That is, when there is no change in phase from the previous symbol, pulses with the same shape are multiplied to generate positive pulses, and when the phase is inverted from the previous symbol, pulses with inverted positive and negative shapes are also multiplied. Produces a negative pulse. Therefore, the detection signal c becomes a negative pulse and a positive pulse depending on whether or not the phase is inverted. The clock regenerator 25 generates a regenerated symbol clock from the detected signal c, and the decoder 23 sequentially samples and discriminates the detected signal c using the timing thereof, and then, according to the polarity of the code of the discrimination point, If it is positive, it is determined to be 1, and if it is negative, it is determined to be -1, and the decoded data string d' _m is output.

The bandpass means 21 may be composed of only a bandpass filter, or as shown in FIG. 6, the bandpass filter 211 and the frequency mixer 212.
And the local oscillator 213. In this case, the input signal is converted by the frequency mixer 212 into a frequency band having a difference from the local oscillation signal which is the output of the local oscillator 213, and then band-limited by the band pass filter 211, and the frequency-converted spread spectrum signal is obtained. Only part of the frequency components of the signal a is extracted and output as the intermediate signal b.

Now, let the oscillation frequency of the local oscillator 213 be f
_{If L} , (Equation 3) becomes (Equation 8),

[0032]

Equation 8] b (t) = Re [δ m · q '(t) · expj {2π
(f _c −f _L ) t}] (Equation 4) becomes (Equation 9),

[0033]

B _d (t) = b (t−T) = Re [δ _m−1 · q ′ (t) · expj {2π (f _c −f _L ) t} · expj {-2
π (f _c -f _L ) T}] (Equation 5),

[0034]

## EQU10 ## By accurately setting T or adjusting the phase of the output signal of the symbol delay unit 221, so that expj {−2π (f _c −f _L ) T} = 1 is satisfied, (Equation 6) representing the delayed intermediate signal b _d is (Equation 1)
1).

[0035]

Equation 11] _{b d (t) = Re [} δ m-1 · q '(t) · expj {2π (f c -f L) t}] Similarly, in the output of the multiplier 222, low-pass The low-frequency component extracted by the filter 223, that is, the detected signal c, is subjected to multiplication of (Equation 8) and (Equation 11) to obtain a harmonic component of expj {4π (f _c -f _L ) t}. It is understood that the result of (Equation 7) is obtained by using (Equation 1) excluding the component term, and similarly, the determination data is obtained by determining the polarity of the detection signal c. Note that (Equation 1
By transforming 0), k is an integer,

[0036]

F _L = f _c −k × (1 / T)
(K is an integer) is obtained, and the oscillation frequency f _L of the local oscillator 213 must be a frequency separated from the frequency f _{c of the} carrier S1 by a frequency interval that is an integral multiple of the symbol rate 1 / T.

For example, the oscillation frequency f of the local oscillator 213
_{If L} is (Equation 13),

[0038]

F _L = f _c −n × (1 / T)
(N is an integer) The spread spectrum signal a is converted into a spread spectrum signal having a center frequency n / T. Therefore, here, for example, as the band pass filter 211, the center frequency is (n
+2) / T and pass band width 2 / T are used, the intermediate signal b is equivalently the spread spectrum signal a.
Is a signal with a partial frequency component (bandwidth 2 / T) of
The frequency component of the intermediate signal b does not include the component of the frequency f _c .

As described above, in the data transmitting / receiving apparatus of this embodiment, the spread spectrum signal a received by the antenna 1 is transmitted.
Among the frequency components of, without equal signal components to the frequency f _c of the carrier wave S1 output from the carrier generator 4 takes out the other partial band signals to generate an intermediate signal b, the intermediate signal Detection and decoding can be performed using b. Therefore, the carrier wave S whose level is higher than that of the intermediate signal b
1 also (frequency f _c) is leaked from the carrier generator 4 does not interfere with the intermediate signal b to the carrier S1 is passed through the band-pass means 21. From this, in this embodiment,
Since it is not necessary to suppress the jump of the carrier wave S1 leaking from the carrier wave generator 4 into the band pass means 21, it is not necessary to use a frequency divider or switch as described in the section of "Prior Art", and a circuit can be realized. It will be easier.

In the above embodiment, the case of two-phase phase modulation has been described, but the detection process is the same for multi-level modulation of four phases, eight phases, etc. The difference is that the differential detector 22 has two systems with orthogonal axes added, and that the decoder 23 discriminates and determines the detection signal c to obtain a determination symbol data string, and then performs parallel / serial conversion. By doing so, the decoded data string d ′ _m which is a bit string is output (for example, WRBennet, JRDavey, “Data transmission”, Lattice).

Further, in the above embodiment, the spread modulation signal q is a pseudo random pulse waveform having a constant amplitude generated by the pseudo random sequence, but the present invention is not limited to this, and other noise-like signals or those shown in FIG. It may be a chirp signal as shown. The waveform in the detection process using the chirp signal is shown in FIG. That is, when the pass band of the band pass means 21 is B1 in FIG. 8A,
The intermediate signal and the detection signal are b1 and c in FIG. 8B, respectively.
8 and the pass band of the band pass means 21 is B2 in FIG. 8A, the intermediate signal and the detection signal are respectively as shown in FIG.
It becomes b2 and c2 of (b).

In the above embodiment, the period of the spread modulation signal q is equal to the symbol period T of the primary modulation signal p, but it is 1 / n of the symbol period T of the primary modulation signal p (n is a natural number). Alternatively, the delay detection may be performed using the symbol period T of the primary modulation signal p that is n times (n is a natural number) and the symbol delay device 221 that has a delay time that is n times the symbol period T. .

FIG. 9 is a block diagram of a data transmitting / receiving apparatus of the second embodiment according to the present invention. In FIG. 9, 3
Is a local oscillator, 190 is a transmitting unit, 200 is a receiving unit, in the transmitting unit 190, 5 is a first mixer, 6 is a band pass filter, 7 is a high frequency amplifier, and in the receiving unit 200,
8 is a band pass filter, 9 is a high frequency amplifier, 10 is a second
It is a mixer. In addition, in FIG. 9, the constituent elements to which the same numbers as in the embodiment of FIG. 1 are added are the same constituent elements as the embodiment of FIG. The second embodiment of the present invention will be described below with reference to FIG.

The transmitting section 190 is configured to perform frequency conversion on the spread spectrum signal a which is the output of the transmitting section 19 of FIG. That is, at the time of transmission, the transmission section 190 obtains the spread spectrum signal a (intermediate frequency f _c ) obtained in the same manner as the transmission section 19 of FIG.
Is input to the first mixer 5 and mixed with the local oscillation signal (frequency f _a ) of the local oscillator 3 to generate the frequency f0 (f0 = f
After being frequency-converted to _{( a} + f _c ), it passes through the band-pass filter 6, is amplified by the high-frequency amplifier 7, and is radiated into space through the transmission / reception changeover switch 2 and the antenna 1 connected to the transmission section side.

On the other hand, the receiving section 200 receives at the antenna 1.
The spread spectrum signal of frequency f0
f_c Frequency conversion to the spread spectrum signal a of
Is configured to perform detection and demodulation in the same manner as the receiving unit 20 of
It was a thing. That is, the receiving unit 20 at the time of reception
0 is the spread spectrum signal received by antenna 1
After (center frequency f0) is amplified by the high frequency amplifier 8,
Passes through the band pass filter 9 and is input to the second mixer 10.
The local oscillation signal of the local oscillator 3 (frequency f _a ) Mixed with
Intermediate frequency f_c(F_c= F0-f_a) To frequency conversion
Thus, the spread spectrum signal a is obtained. Reception of Figure 1
As with the section 20, the spread spectrum signal a is
It is input to the pass filter 21 and is input to the band pass filter 21.
In the same manner as the first embodiment, the center frequency f_c Excluding
Only the fractional frequency components are extracted and the intermediate signal b is obtained.
Be done. After that, from the intermediate signal b to the first embodiment.
In the same way as the explanation of
You can get the data. Therefore, even in the receiving unit 200,
Frequency f leaking from carrier wave generator 4_cCarrier wave S1 of
The carrier wave S1 that does not pass through the band pass filter 21
Degradation of reception sensitivity due to does not occur.

As described above, according to the second embodiment,
Carrier wave S1 leaking from the carrier wave generator 4 into the receiving section 200
Since there is no deterioration in reception sensitivity due to (frequency f _c ), the same intermediate frequency can be used by the transmission unit 190 and the reception unit 200. Therefore, a local oscillation signal for converting the spread spectrum signal a in the transmitting unit 190 from the intermediate frequency f _c to the frequency f 0 and a local oscillation signal for converting the spread spectrum signal received in the receiving unit 200 from the frequency f 0 to the intermediate frequency f _c The local oscillation signal can have the same frequency. Therefore, the present embodiment has an advantage that the common local oscillator 3 can be used for frequency conversion of the transmission unit 190 and the reception unit 200.

FIG. 10 is a block diagram of a data transmitting / receiving apparatus of the third embodiment according to the present invention. In FIG. 10, 191 is a transmission unit, 201 is a reception unit, 17 is a packet assembler, 21A to 21B are band pass means, and 28A to 2 are shown.
8B is a demodulator, 26A to 26B are unique word detectors, 27A to 27B are packet extractors, and 29A to 29B.
Is an error detector, and 24 is a decision selector. FIG. 11 is a block diagram showing a configuration example of the demodulation units 28A and 28B,
30 is an amplifier, 22 is a detector, 25 is a clock regenerator,
Reference numeral 23 is a decoder, which is the same as that used in the first and second embodiments.

Further, FIG. 12 showing an example of the code structure of the data packet output from the packet assembler 17 will be described below.
FIG. 12A illustrates an example of a data packet observed in the determination data string output from the demodulators 28A and 28B.
The operation will be described below with reference to FIG. 13 which shows an outline of the spectrum of the signal of each part (b).

First, the operation during transmission will be described. In this embodiment, the configuration and operation of each unit of the transmission unit 191 are almost the same as those of the transmission unit 190 of the second embodiment shown in FIG. 9, except that the packet assembler 17 is added and the transmission data is packetized. A burst-like spread spectrum signal a corresponding to each packet.
The output to the mixer 5 is different. That is, the transmission data is first divided into predetermined numbers of bits, and
As shown in an example in (a), it becomes the information data 93, and the preamble 91, the unique word 92, and the error detection bit 94 are added to form the data packets 61 to 64. Similar to the first embodiment, the data packets 61 to 64 are taken in by the modulator 16 in synchronization with the symbol clock CK, become the burst-like primary modulation signal p corresponding to each packet, and the spread modulation signal q. And the spread spectrum signal a is obtained. This spread spectrum signal a
Is subjected to frequency conversion and amplification as in the second embodiment, and then radiated into space via the transmission / reception change-over switch 2 and the antenna 1 connected to the transmitter side.

Since the steep rise and fall of the burst causes the transmission spectrum width to widen, a ramp waveform whose envelope curve changes smoothly may be added to the leading and trailing edges of the burst. Unique word 9
As will be described later, 2 is a fixed bit pattern string inserted to find a corresponding data packet in the decoding process in the receiving unit 201. On the other hand, the error detection bit 94
Is a variable bit pattern string inserted by the receiving unit 201 to check whether or not a bit error has occurred in the information data 93 and the error detection bit 94 itself. As the error detection bit 94, a parity code or a CRC (Cyclic Redundacy Check) code is actually used.

Next, the operation at the time of reception will be described. The configuration and operation of the receiving unit 201 from the antenna 1 to the second mixer 10 are similar to those of the second embodiment shown in FIG. The processing of the spread spectrum signal a whose center frequency is the intermediate frequency f _c is described below.

The spread spectrum signal a is band-limited by the bandpass means 21A to 21B and becomes the intermediate signal b. FIG. 13 exemplifies the outline of the spectrum of the received spread spectrum signal a and the case where the band pass means 21A to 21B can have four bands (B1 to B4).

As shown in FIG. 13, the bandpass means 21A.
21B can have a pass band of the first embodiment or the second embodiment.
Similarly to the embodiment of FIG.
The frequency f _c of 1 is not included. Therefore, also in the present embodiment, as in the first and second embodiments, the carrier wave S1 (frequency f _c ) leaking from the carrier wave generator 4 is received by the receiving unit 2.
Even when the signal leaks into 01, the received signal sensitivity is not deteriorated due to it.

The bandpass means 21A to 21B are each composed of a bandpass filter, and each corresponds to all or part of the passbands B1 to B4. The pass band is not limited to four as shown in FIG. 13, but may be two or more. Similarly, as shown in FIG. 10, the number of band pass means 21A to 21B may be two or more, and two cases are also included as a typical example.

The intermediate signal b thus obtained is detected and decoded by the demodulators 28A-28B, respectively, as in the first embodiment, and output as a decision data string d' _m from the demodulators 28A-28B. To be done.

This judgment data string d' _m is shown in FIG.
The data packets 61 ′ to 64 ′ of FIG. 12B having the same structure corresponding to the data packets 61 to 64 of FIG. The unique word detectors 26A to 26B collate the determination data string d' _m with the fixed pattern of the unique word at any time, and when they detect a match, they output a frame signal. The packet extractors 27A-27B determine the information data 93 'and the error detection bit 9 based on the timing of this frame signal.
The decoded data packet 95 'consisting of 4'is extracted and delivered to the error detectors 29A-29B. Error detector 29A-
29B each detect a bit error in the decoded data packet 95 ′ based on the error detection bit 94 ′, pass the result to the decision selector 24, and also include the information data 93 ′ in the decoded data packet 95 ′. Judgment selector 2
Hand over to 4. The judgment selector 24 selectively connects only the information data 93 ′ of the system in which no bit error is detected, and outputs the decoded data as the final output of the receiving unit 201.

As described above, according to the configuration of the present embodiment shown in FIG. 10, even when the carrier wave S1 having the frequency f _c leaks from the carrier wave generator 4 to the receiving section 201, the carrier wave S1 is passed through the band pass means. Since it does not pass through 21A-21B,
Packet data can be transmitted / received without deterioration of received signal sensitivity due to leakage of carrier wave S1.

If only packet data is transmitted / received without deterioration of received signal sensitivity due to leakage of the carrier wave S1 having the frequency f _{c from} the carrier wave generator 4 into the receiver 201, the spectrum shown in FIG. The system for processing the spread signal a is only one surrounded by a dotted line 300 in FIG.
Although only one signal processing system is required and the judgment selector 24 is not necessary, the following effects can be obtained by providing a plurality of processing systems for the spread spectrum signal a and providing the judgment selector 24 as shown in FIG. Occurs.

As shown in FIG. 13, when the interfering wave j is added in the transmission path, the apparatus of the present embodiment allows partial bands B1 to B4 of the spread spectrum signal a to be transmitted.
Since the band pass means 21A to 21B for passing only the band pass means 21A to 21B are provided, in the example of FIG.
If one or more of these are set to the pass band B1, the intermediate signal b input to the detector of the system is not affected by the interfering wave j, and normal reception is performed. Therefore,
In the other systems, even if the reception is not normally performed and even if the error detector detects a bit error, if there is at least one system that can avoid the influence of the interfering wave j as described above, The error detector does not detect a bit error, and the decision selector 24 selects the information data 93 'of that system and outputs it as decoded data, so that normal reception is continued.

Further, the band pass means 21A to 21B are the same as the first embodiment, like the band pass means 21 shown in FIG. 6, the band pass filter 211 and the frequency mixer 21.
2 and the local oscillator 213. However, in this case, it is expressed in the first embodiment (Equation 12).
Therefore, the oscillation frequency f _L of the local oscillator 213 must be a frequency separated from the frequency f _{c by} a frequency interval that is an integral multiple of the symbol rate 1 / T. Local oscillator 21
Reference numeral 3 generally comprises a PLL (Phase Locked Loop) synthesizer, which varies the frequency of the local oscillation signal at frequency intervals that are integer multiples of the symbol rate 1 / T, or the local oscillators of the bandpass means 21A to 21B. Reference numeral 213 is for generating a local oscillation signal having a frequency different by this frequency interval. Equivalently, by changing the frequency of the local oscillation signal, the components of the original spread spectrum signal a having different frequency components can be extracted as the intermediate signal b. When the center frequencies of the respective intermediate signals of the band pass means 21A to 21B are selected to be the same and the frequencies of the local oscillation signals are made different to obtain different pass bands, the band pass filters 211 and the demodulators 28A to 28A to
The same 28B can be used, and the amplifier 30 and the detector 22 inside the demodulation units 28A to 28B shown in FIG.
Has the advantage of being easy to implement, since it is only necessary to guarantee operation in a relatively narrow frequency range corresponding to the pass band.

[0061]

As is apparent from the above description, according to the present invention, the receiving section is a portion of the frequency component of the received modulated signal which does not include the frequency of the carrier wave output from the carrier wave generator of the transmitting section. Since it has at least one bandpass means for extracting only the frequency component of a specific band and at least one wave detector for detecting the output signal of the bandpass means, a frequency divider or a switch for switching the operation of the frequency divider is required. In addition, there is an advantage that the deterioration of the reception signal sensitivity due to the leakage of the carrier wave from the transmitter to the receiver can be eliminated.

[Brief description of drawings]

FIG. 1 is a block diagram of a data transmission / reception device of a first embodiment according to the present invention.

FIG. 2 is a diagram showing an outline of a spectrum of a signal in the receiving unit of the first embodiment.

FIG. 3 is a block diagram showing a configuration example of a modulator according to the first embodiment.

FIG. 4 is a block diagram showing a configuration example of a detector in the first embodiment.

5A is a diagram showing an example of a signal waveform of each part of the transmitting unit in the first embodiment, and FIG. 5B is a diagram showing an example of a signal waveform of each unit of the receiving unit. Is.

FIG. 6 is a block diagram showing a configuration example of a bandpass means in the first embodiment.

FIG. 7 is a diagram showing an example of a signal waveform of each part of the transmission unit when the spread modulation signal is a chirp signal in the first embodiment.

FIG. 8A is a diagram showing an outline of a spectrum of a signal in a receiving section when a spread modulation signal is a chirp signal in the first embodiment, and FIG. 8B is a diagram showing that case. It is the figure which showed an example of the signal waveform of each part of a receiving part.

FIG. 9 is a block diagram of a data transmitting / receiving apparatus according to a second embodiment of the present invention.

FIG. 10 is a block diagram of a data transmitting / receiving apparatus according to a third embodiment of the present invention.

FIG. 11 is a block diagram showing a configuration example of a demodulation unit in the third embodiment.

FIG. 12 (a) is a diagram showing an example of a code structure of a transmission data packet in the third embodiment, and FIG. 12 (b).
FIG. 6 is a diagram illustrating an example of a data packet observed in the determination data string.

FIG. 13 is a diagram showing an outline of a spectrum of a signal in a receiving unit in the third embodiment.

FIG. 14 is a block diagram of a conventional data transceiver.

[Explanation of symbols]

1 Antenna 2 Transmission / Reception Selector Switch 3 Local Oscillator 4 Carrier Wave Generator 5 First Mixer 10 Second Mixer 16, 160 Modulator 17 Packet Assembler 19, 101, 190, 191 Transmitter 20, 102, 200, 201 Receiver 21, 21A to 21B Band pass means 22 Detector 23 Decoder 24 Judgment selector 26A to 26B Unique word detector 27A to 27B Packet extractor 28A to 28B Frame error detector 29A to 29B Error detector

Claims (7)

[Claims] 1. A data transmitter / receiver for transmitting and receiving data in a time division manner using the same frequency, wherein a carrier wave generator for outputting a carrier wave and a carrier wave output from the carrier wave generator are transmitted by using transmission data. A transmitter having a modulator for outputting a digitally modulated modulated signal, and at least one band-passing means for taking out only a frequency component of a partial band which does not include the frequency of the carrier among frequency components of the received modulated signal. And a receiving unit having at least one detector for detecting an output signal of the bandpass means, and a receiver having a decoder for decoding the detected signal. 2. The transmitting unit has a first mixer for converting the frequency band of the modulated signal, and the receiving unit has a second mixer for converting the frequency band of the received signal. The data transmitting / receiving apparatus according to claim 1, wherein both the first mixer and the second mixer are provided with a local oscillator that supplies a local oscillation signal for frequency conversion. 3. The transmission unit has a spread modulation signal generator,
3. The data transmitting / receiving apparatus according to claim 1, wherein a spread spectrum signal obtained by multiplying the digitally modulated primary modulation signal by a spread modulation signal having a wider band than the primary modulation signal is output. 4. The data transmitting / receiving apparatus according to claim 3, wherein the spread modulation signal is a chirp signal obtained by repeatedly sweeping the frequency of a sine wave in each cycle. 5. The transmission data is packet data including at least a unique word and an error detection bit, and the reception unit generates at least one clock from each of the at least one detection signal output from the detector. A regenerator, at least one decoder that outputs a judgment data string from the detected signal and the reproduction clock, and a head of each decoded data packet by detecting the unique word from at least one judgment data string. At least one unique word detector to find out, at least one packet extractor for extracting each of the decoded data packets from the determination data string based on the frame signal output from the unique word detector, and the error detection bit Use the decrypted data packet At least one error detector for detecting a bit error in the decoded data packet, and the decoded data is obtained from the decoded data packet determined to have no bit error by the error detector. Item 3. The data transmitting / receiving device according to item 3 or 4. 6. The digital modulation is differential phase modulation, the period of the spread modulation signal is an integral multiple or a fraction of the symbol period of the primary modulation signal, and the detector detects the intermediate signal and the intermediate signal. 6. The data transmitting / receiving apparatus according to claim 3, wherein the data transmitting / receiving apparatus is a delay detector that obtains a detection signal by multiplying the delay signal delayed by an integer multiple of the symbol period of the primary modulation signal. 7. The bandpass means comprises a frequency mixer, a local oscillator for supplying a local oscillation signal to the frequency mixer,
And a bandpass filter for extracting only a signal component of a partial band of the output of the frequency mixer converted into a frequency band having a difference from the frequency of the local oscillation signal, and the frequency of the local oscillation signal as a carrier wave. Of the local oscillation signal by changing the frequency of the local oscillation signal by an integer multiple of 1 of the symbol cycle, or by arranging the frequencies of the local oscillation signals at frequency intervals of an integer multiple of 1 of the symbol cycle excluding the frequency of the carrier wave. 7. The data transmitting / receiving apparatus according to claim 6, wherein an oscillator is used.