JPH09181646A - Optical radio modulator, optical radio demodulator and optical radio modem - Google Patents

Abstract

PROBLEM TO BE SOLVED: To simultaneously use plural optical radio modems inside a limited section by constituting an optical radio modulator by a spread spectrum modulation means, a driving means and a light emitting means. SOLUTION: The spread spectrum modulation means 11 outputs primary modulation waves M(t) for which a carrier wave frequency f0 is modulated based on information signals D(t) to a frequency dividing means 12 and a multiplication means 14. The frequency dividing means 12 frequency-divides the primary modulation waves M(t) and outputs clock signals MF(t) for which carrier waves and a modulation index are lowered to 1/(a frequency division number) to a spread code generation means 13. The means 13 generates high-speed M sequence codes based on the input clock signals MF(t) and outputs them to the multiplication means 14 as spread codes p(t). The means 14 multiplies the modulation waves M(t) an the spread codes p(t) and outputs the result to the driving means 15 as spread spectrum modulation waves SM(t). The means 15 outputs driving signals SM1 (t) based on the modulation waves SM(t) to the light emitting means 16.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical wireless modulator, an optical wireless demodulator, and an optical wireless modulator / demodulator, and more particularly to an optical wireless modulator that enables optical wireless multiplex transmission and an optical wireless demodulator. And an optical wireless modulator / demodulator.

[0002]

2. Description of the Related Art As a conventional optical wireless modulation / demodulation device, an optical remote control device (optical remote control device) used for remote control of home AV equipment (home audio / video equipment) is known. FIG. 8 shows a block diagram of a main part of an optical wireless modulator of an optical remote controller (optical remote controller) as a conventional example.

In FIG. 8, an optical wireless modulator of an optical remote controller (optical remote controller) comprises a keyboard 40, a carrier wave modulating means 41, a driving means 42 and an optical wireless light emitting means 43.

The keyboard 40 outputs the data D (t) to the carrier wave modulating means 41. The carrier wave modulation means 41 shifts the carrier wave to FSK (FREQUENCYSHIFT K) based on the data D (t).
The data modulating wave S _M (t) modulated by EYING) or PSK (PHASE SHIFT KEYING) is output to the driving means 42. The drive means 42 creates a drive data modulated wave S _M1 (t) suitable for driving the optical wireless light emitting means 43 (LED) based on the data modulated wave S _M (t), and the drive data modulated wave S _M1 (t) is generated.
_{The M1} (t) is output to the optical wireless light emitting means 43 (LED). The optical wireless light emitting means 43 (LED) emits an optical wireless modulated wave S _C (t) obtained by converting an electric signal of the drive data modulated wave S _M1 (t) into an optical signal.

FIG. 9 shows a block diagram of a main part of an optical wireless demodulation device of an optical remote control device (optical remote control device) as a conventional example.

In FIG. 9, an optical wireless demodulation device of an optical remote control device (optical remote control device) includes a light receiving means 4
4 and demodulation means 45. A pin photodiode is used as the light receiving unit 44, and the radiated optical wireless modulation wave S _C (t) is received and converted into an electric signal, and the data modulation wave S _D (t) is output to the demodulation unit 45. Demodulation means 45
Is the demodulated data modulated wave S _D (t) to demodulate the data D (t) from the keyboard 40 of the optical wireless modulator into the demodulated data D _D.
Output as (t).

[0007]

FIG. 10 shows an example of unnecessary radiation characteristics of a high frequency fluorescent lamp used in offices and general households. As shown in FIG. 10, although the basic spectrum of the high frequency fluorescent lamp is several 100KH _Z (i), since the high-frequency component is extends to a frequency band of several MH _Z (b), a conventional optical wireless modulator in, there is a problem that the carrier frequency band to be used to avoid interference with the high-frequency component of a high frequency fluorescent lamp is a high frequency band of 10 number MH _Z several MH _Z.

Further, since the optical wireless light emitting means (LED) of the optical wireless modulator generally has a low luminous efficiency with respect to the driving power, a large driving current is momentarily supplied to the optical wireless light emitting means to increase the light emission amount. Square wave drive or pulse drive is used to suppress the amount of heat generation. FIG. 11 shows an example of frequency spectrum characteristics of the optical wireless modulated wave of the optical wireless modulator. As shown in FIG. 11, in order to drive the optical wireless light emitting means with a pulse current, an unnecessary radiation spectrum over a wide frequency band including the frequency S _M (f) of the data modulation wave S _M (t) is generated by the pulse current. Therefore, a plurality of uses of the optical wireless modulator / demodulator by the frequency division multiplexing method, which is considered to be a promising multiplex method, in a limited space causes a problem in frequency interference between the optical wireless modulators / demodulators, which is not practical.

In addition, in the optical wireless modulator / demodulator using the time division multiplex as the multiplexing system, it is necessary for each optical wireless modulator / demodulator to maintain a synchronous relationship, which is a major limitation and has not spread. Not in. A plurality of uses of the optical wireless modulator / demodulator by the asynchronous time division multiplex system in a limited space cannot be put into practical use because there is no synchronization between the optical wireless modulators / demodulators, which causes interference between the optical wireless modulators / demodulators. There is.

However, there is a problem that a plurality of conventional optical wireless modulators / demodulators cannot be used practically in a limited space.

The present invention has been made to solve the above problems, and an object thereof is to enable a plurality of optical wireless modulator / demodulators to be used simultaneously within a limited section and to interfere with other electronic equipment. Another object of the present invention is to provide a reliable optical wireless modulator / demodulator with high interference rejection capability.

[0012]

A plurality of optical wireless modulators / demodulators according to a first aspect of the present invention have different spreading codes and have a code division multiplexing function.

In the optical wireless modulator / demodulator according to the present invention, the plurality of optical wireless modulators / demodulators according to claim 1 have different spreading codes and have a code division multiplexing function.
It is possible to use a plurality of optical wireless modulators / demodulators, which was not possible under the high efficiency driving of the above, as code division multiplexing in the limited space range at the same time and the same frequency band.

A plurality of optical wireless modulators / demodulators according to a second aspect of the present invention are characterized in that the optical wireless modulator is provided with optical wireless light emitting means having directivity.

Since the optical wireless modulator / demodulator according to the present invention includes the optical wireless light emitting means having directivity in the plurality of optical wireless modulators according to the second aspect, the multiplex having both the code division multiplexing and the optical space division multiplexing. System, and more optical wireless modulators / demodulators can be used in a limited space.

An optical wireless modulator according to a third aspect of the present invention comprises a spread spectrum modulating means for outputting a spread spectrum modulated wave obtained by spread spectrum modulating an information signal, and a driving means for outputting a drive signal based on the spread spectrum modulated wave. And a light emitting means for converting the drive signal into an optical signal and transmitting the optical signal as an optical wireless modulation wave, and the spread spectrum modulation means is an information modulation means for outputting a primary modulation wave obtained by modulating the information signal. Frequency dividing means for dividing the primary modulated wave to output a clock signal, spreading code generating means for generating a spreading code based on the clock signal and outputting the spreading code, primary modulated wave and spreading code And multiplying means for outputting a spread spectrum modulated wave multiplied by and.

An optical wireless modulator according to the present invention comprises:
In the optical wireless modulator described above, a spread spectrum modulation means for outputting a spread spectrum modulated wave obtained by spread spectrum modulating an information signal, a driving means for outputting a drive signal based on the spread spectrum modulated wave, and a drive signal as an optical signal And a light emitting means for converting and transmitting the optical signal as an optical wireless modulated wave, wherein the spread spectrum modulating means divides the primary modulated wave with the information modulating means for outputting a primary modulated wave obtained by modulating the information signal. Frequency division means for frequency-dividing and outputting a clock signal, spreading code generation means for generating a spreading code based on the clock signal and outputting the spreading code, and spread spectrum modulation in which the primary modulated wave and the spreading code are multiplied Since it is provided with a multiplying unit that outputs a wave, stable and stable transmission and reception can be performed against interference due to unnecessary radiation from electric equipment and the power density of the spread spectrum modulated wave can be improved. Since again, it is possible to reduce the influence on other electric devices.

An optical wireless demodulation device according to a fourth aspect of the present invention demodulates a light receiving means for receiving the optical wireless modulated wave and converting it into an electric signal, and a spread spectrum modulated wave obtained by passing the output of the light receiving means through a bandpass filter. Despread demodulation means for performing despread demodulation by multiplication using the spreading code for use to output a despread demodulation signal, a despread demodulation signal for a primary modulated wave obtained through a bandpass filter, and an amplification means. And a primary demodulation unit including a phase comparison unit, a loop filter, and a voltage controlled oscillation unit for performing primary demodulation and outputting an information signal, and a sliding correlation signal is generated and output to the despreading demodulation unit. Oscillation means for sliding correlation, frequency division means for dividing the primary modulated wave to output a clock signal, synchronization control means for binarizing the output signal of the phase comparison means and outputting a switching signal, and switching Switching means for switching between the sliding correlation signal and the clock signal based on the signal, the spreading code generating means for outputting the demodulation spreading signal based on the clock signal, and the multiplication of the spread spectrum modulated wave and the demodulation spreading signal. And a multiplying unit for outputting a despread demodulation signal.

An optical wireless demodulation device according to the present invention comprises:
In the optical wireless demodulation device described, the light receiving means for receiving the optical wireless modulated wave and converting it into an electric signal, and the spread spectrum modulated wave obtained by outputting the output of the light receiving means through a bandpass filter by using a spreading code for demodulation. Information is obtained by first demodulating a primary modulated wave obtained through a despread demodulation means for performing despread demodulation by multiplication and outputting a despread demodulated signal, a despread demodulated signal through a bandpass filter, and an amplifying means. And a primary demodulating means including a phase comparing means, a loop filter and a voltage controlled oscillating means for outputting a signal, and a sliding correlation oscillating means for generating and outputting a sliding correlation signal to the despreading demodulating means. The frequency dividing means for dividing the primary modulated wave to output a clock signal and the output signal of the phase comparing means are divided into two.
Synchronization control means for digitizing and outputting a switching signal; switching means for switching a sliding correlation signal and a clock signal based on the switching signal; spreading code generating means for outputting a demodulation spreading signal based on the clock signal; Since a multiplication means for multiplying the spread spectrum modulated wave and the spread signal for demodulation and outputting the despread demodulated signal is provided, stable and stable transmission and reception can be performed against interference due to unnecessary radiation from electric equipment, Further, since the power density of the spread spectrum modulated wave is small, it is possible to reduce the influence on other electric devices.

An optical wireless modulator according to a fifth aspect of the present invention is the optical wireless modulator according to any one of the first, second, and third aspects, wherein the primary modulated wave input to the multiplying means and the spread code generating means. It is characterized in that it is a synchronous spread modulation that is synchronized with the clock signal input to.

An optical wireless modulator / demodulator according to the present invention is the optical wireless modulator according to claim 5, wherein the primary modulated wave input to the multiplication means and the clock signal input to the spread code generation means are synchronized. Type diffusion modulation, so with a simple configuration,
The optical wireless modulator can be put to practical use by a simple circuit operation.

An optical wireless demodulating device according to a sixth aspect is the optical wireless demodulating device according to any one of the first, second and fourth aspects, in which a spread spectrum modulated wave and a spread code generating means input to a multiplying means are provided. The synchronous despreading demodulation is synchronized with the clock signal input to the.

An optical wireless demodulation device according to the present invention comprises:
Since the optical wireless modulator described above is a synchronous despread demodulation in which the spread spectrum modulated wave input to the multiplication means and the clock signal input to the spread code generation means are synchronized, a simple configuration and a simple circuit The operation makes it possible to put the optical wireless demodulation device into practical use.

[0024]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described based on embodiments shown in the drawings. FIG. 1 is a block diagram of the essential parts of an optical wireless modulator according to the present invention. FIG. 2 is a frequency spectrum diagram of the primary modulation wave M (t) and the spread spectrum modulation wave S _M (t) of the optical wireless modulator according to the present invention. In FIG. 1, the optical wireless modulator 1 includes a spread spectrum modulator 10 including an information modulator 11, a frequency divider 12, a spread code generator 13, and a multiplier 14, and a driver 15.
And a light emitting means 16.

The information modulating means 11 is a digital information signal D.
Based on (t), the carrier frequency f ₀ is subjected to MSK (minimum shift keying) modulation with a modulation index of 0.5 as primary modulation, and a primary modulated wave M (t) is output to the frequency dividing means 12 and the multiplying means 14. . In [A] of FIG.
The spectrum of the next modulated wave M (t) is shown.

The frequency dividing means 12 divides the primary modulated wave M (t) and outputs a carrier signal and a clock signal M _F (t) whose modulation index is reduced by a factor of 1 to the spread code generating means 13. To do.

The spread code generating means 13 generates an M sequence code that is faster than the transmission rate of the information signal D (t) based on the input clock signal M _F (t), and uses this M sequence code as the spread code. It is output to the multiplication means 14 as p (t).

The multiplying means 14 is composed of a multiplier or a double balanced mixer (DBM) and multiplies the modulated wave M (t) by the spread code p (t) as the secondary modulation, and as a result M
(T) × p (t) is output to the driving means 15 as a spread spectrum modulated wave S _M (t). FIG. 2B shows the spectrum of the spread spectrum modulated wave S _M (t) which is a wide band modulated wave.

The driving means 15 is a spread spectrum modulated wave S _M.
The drive signal S _M1 (t) based on (t) is output to the light emitting means 16, the light emitting means 16 is light intensity modulated as the third-order modulation, and the light emitting means 16 emits the optical wireless modulated wave S _C (t). Output.

FIG. 3 is a block diagram of the essential parts of an optical wireless demodulator according to the present invention. In FIG. 3, the optical wireless demodulating device 2 includes a light receiving unit 20, a despreading demodulating unit 21, a band pass filter 29, an amplitude limiting amplifying unit 30, a primary demodulating unit 3.
1, a low-pass filter 32. The despreading demodulation means 21 includes a bandpass filter 22, a multiplication means 23, a sliding correlation oscillation means 24, a frequency division means 25, a bandpass filter 33, a synchronization control means 26, and a switching means 2.
7 and spreading code generating means 28. The primary demodulation means 31 includes a phase comparison means 31A and a loop filter 31.
B, and a voltage controlled oscillator 31C.

The light receiving means 20 receives the optical wireless modulated wave S _C (t) which is an optical signal by a light receiving means such as a pin photodiode and converts it into an electric signal, which is a spread spectrum modulated wave S.
_D1 (t) is output to the bandpass filter 22. The bandpass filter 22 multiplies the spread spectrum modulated wave S _D (t) by passing only a predetermined frequency band of the spread spectrum modulated wave S _D1 (t) and removing unnecessary components outside the band.
Output to

The sliding correlation oscillating means 24 has a frequency (f ₀ / n + Δf) of the sliding correlation signal G for acquiring the initial synchronization necessary for performing the despread demodulation.
(T) is output to the switching means 27 as a clock signal.
The frequency divider 25 is the voltage controlled oscillator 3 of the primary demodulator 31.
The output signal M _DC (t) from 1C is divided into 1 / n to output a clock signal M _DF (t) to the switching means 27.

The bandpass filter 33 is the primary demodulation means 3
1 demodulation correlation noise component D _EN (t) that has passed only the middle frequency band of the output signal D _E (t) from the phase comparison means 31A
Is output to the synchronization control means 26. The synchronization control means 26 binarizes the demodulated correlation noise component D _EN (t) and switches the switching signal S.
Switching means _W (t) to be output to the switching means 27 27, the output signal M _DC switching signal S _W (t) by the initial synchronous acquisition sliding correlation signal G (t) and the voltage controlled oscillator means for the ( clock signal M obtained by dividing t) into 1 / n
_DF (t) is switched and its output is clock signal G _C (t)
To the spreading code generating means 28.

The spread code generating means 28 is the optical wireless modulation means 1
Using the M-sequence code used in the spreading code generation means 13 of
Spreading code p for demodulation based on the clock signal G _C (t)
_D (t) is generated and this demodulation spread code p _D (t) is output to the multiplication means 23. The multiplying means 23 is composed of a double balanced mixer (DBM), and performs spread spectrum modulation by multiplying the spread spectrum modulated wave S _D (t) output from the band pass filter 22 by the demodulation spread code p _D (t). The wave S _D (t) is subjected to correlation demodulation and the despread demodulation signal M _D1 (t)
Get. The band pass filter 29 is a despread demodulation signal M _D1.
The demodulated first-order modulated wave M _D2 (t) is obtained by passing only the predetermined frequency band of (t), and is output to the amplitude limiting amplification means 30.

As described above, the optical wireless modulator of the optical wireless modulator / demodulator outputs the spread spectrum modulating means for spread spectrum modulating the information signal to the spread spectrum and the drive signal based on the spread spectrum modulating wave. The spread spectrum modulating means is provided with a driving means and a light emitting means for converting the driving signal into an optical signal and transmitting the optical signal as an optical wireless modulated wave, and the spread spectrum modulating means outputs information for outputting a primary modulated wave obtained by modulating the information signal. Modulating means, frequency dividing means for dividing the primary modulated wave to output a clock signal, spreading code generating means for generating a spreading code based on the clock signal and outputting the spreading code, and primary modulated wave And a multiplying unit for outputting a spread spectrum modulated wave that is obtained by multiplying a spread code with each other, so that stable transmission and reception can be performed against interference due to unnecessary radiation from electric devices, Since the power density of a spread spectrum modulated wave is small and it is possible to reduce the influence on other electric devices.

FIG. 4 is an explanatory diagram of the operation of initial synchronization acquisition of the optical wireless demodulation device according to the present invention. [A] of FIG. 4 shows the waveform of the demodulated primary modulated wave M _D2 (t) of the bandpass filter 29. When the extended code length is L, the time L1 between the correlation peak time S _P1 and the correlation peak time S _P2 is L1 = L
/ {F ₀ − (f ₀ ± Δf), and the initial synchronization acquisition time T has a relationship of T <L1.

The demodulated primary modulated wave M _D2 (t) of the bandpass filter 29 is supplied to the primary demodulating means 31 via the amplitude limiting amplifying means 30 and is MSK demodulated. The amplitude limiting / amplifying means 30 amplitude-limits and amplifies the demodulated primary modulated wave M _D2 (t), and outputs the output M _D (t) to the primary demodulating means 31. The primary demodulation means 31 is a phase comparison means 31A, a loop filter 3
1B, a PLL including a voltage controlled oscillator 31C. The demodulated primary modulated wave M _D (t) that has been amplitude-limited and amplified is input to the phase comparison unit 31A as the reference signal M _D (t) of the phase comparison unit 31A. The oscillation output signal of the voltage controlled oscillator 31C is used as the comparison signal M _DC (t) in the phase comparator 3
The reference signal M _D (t) and the comparison signal M _DC (t) that are fed back to the phase comparison unit 31A are fed back to the loop filter 31B so that the frequency and the phase of the reference signal M _D (t) match.
The control voltage is output as an error signal D _E (t) to the voltage controlled oscillator 31C via the. The primary demodulation means 31 outputs the error signal D _E (t) as a primary demodulation output signal D _E (t) to the low pass filter 32 and the band pass filter 33,
The output of the low-pass filter 32 is the demodulation information signal D _D (t)
Get.

[B] of FIG. 4 shows the waveform of the demodulation correlation noise component D _EN (t) of the bandpass filter 33. The synchronization control means 26 binarizes the demodulated correlated noise component D _EN (t) to generate the switching signal S _W (t), and [A] in FIG.
Correlation peak time S _P1 and correlation peak time S _{P2 shown in}
The level of the demodulated correlation noise component D _EN (t) becomes a minimum at the time corresponding to, and the switching means 27 is switched by detecting this minimum time.

[C] and [D] of FIG. 4 show the switching timing of the switching means 27. The switching means 27 converts the sliding correlation signal G (t) to the clock signal M.
_{When the} switching operation is performed on _DF (t), the switching operation continues.

The oscillation output signal M _DC (t) of the voltage controlled oscillator 31C of the primary demodulator 31 for MSK demodulation is synchronized with the demodulated primary modulated wave M _D (t) at the frequency f ₀ , and this frequency f ₀ matches the frequency of the primary modulated wave M (t) of the optical wireless modulator 1. Therefore, the clock signal G _C (t) supplied to the spread code generating means 28 via the frequency dividing means 25 and the switching means 27 is also the clock signal M _F (supplied to the spread code generating means 13 of the optical wireless modulator 1. equal to t).
The frequency division number of the frequency division means 25 is equal to the frequency division number of the frequency division means 12 of the optical wireless modulator 1.

The clock signal G _C (t) is supplied to the spread code generating means 28, the initial synchronization acquisition is shifted to the synchronization holding operation, the initial synchronization acquisition is completed, and thereafter the normal MSK is performed.
The demodulation continues and the demodulation information signal D _D (t) is output to the output terminal through the low pass filter 32.

As described above, in the optical wireless demodulation device of the optical wireless modulation / demodulation device, the light receiving means for receiving the optical wireless modulated wave and converting it into an electric signal, and the spread spectrum obtained by the output of the light receiving means through the band pass filter. 1 obtained by despreading demodulation means for despreading demodulating a modulated wave by multiplication with a spreading code for demodulation and outputting a despread demodulation signal; and a despread demodulation signal through a bandpass filter and an amplification means. A primary demodulation means including a phase comparison means, a loop filter, and a voltage controlled oscillation means for primary demodulating the secondary modulated wave and outputting an information signal, and generating a sliding correlation signal in the despread demodulation means. Oscillating means for sliding correlation, which is output in the form of frequency, frequency dividing means for dividing the primary modulated wave to output a clock signal, and synchronization for binarizing the output signal of the phase comparing means and outputting a switching signal. Control means, switching means for switching between the sliding correlation signal and the clock signal based on the switching signal, spreading code generating means for outputting the demodulation spreading signal based on the clock signal, spread spectrum modulated wave and demodulation spreading signal And a multiplication means for outputting a despread demodulated signal by multiplying with, so that stable transmission and reception are possible against interference due to unnecessary radiation from electrical equipment, and the power density of the spread spectrum modulated wave Since it is small, the influence on other electric devices can be reduced.

FIG. 5 is a schematic explanatory view of the code division multiplexing system of the optical wireless modulator / demodulator according to the present invention. FIG. 6 is an explanatory view of the principle of the code division multiplexing system of the optical wireless modulator / demodulator according to the present invention. In FIG. 5, a transmitting terminal (A) spread-spectrum-modulates an information signal a with a spread code p ₁ (t), and further transmits an optical wireless modulated wave a1 whose light intensity is modulated by a light emitting means based on the spread-spectrum modulated wave. . The transmitting terminal (B) spread-spectrum-modulates the information signal b with the spread code p ₂ (t), and further transmits the optical wireless modulated wave b1 whose light intensity is modulated by the light emitting means based on the spread-spectrum modulated wave. Sending terminal (C)
Performs spread spectrum modulation of the information signal c with a spread code p ₃ (t), and further transmits an optical wireless modulated wave c1 whose light intensity is modulated by the light emitting means based on the spread spectrum modulated wave.

The optical wireless modulated waves emitted from the respective transmitting terminals are spatially combined, and the spatially combined waves are received by the light receiving means of each demodulating terminal. The demodulation terminal (D) correlatively demodulates the received spatially synthesized wave with the demodulation spreading code p ₁ (t), and thus obtains the information signal a. The demodulation terminal (E) correlatively demodulates the received spatially synthesized wave with the demodulation spreading code p ₂ (t), and thus obtains the information signal b. Since the demodulation terminal (F) performs correlation demodulation on the received spatially synthesized wave with the demodulation spreading code p ₃ (t), the information signal c
Get.

[A] of FIG. 6 shows an MSK modulated wave which is the primary modulation of the carrier of the carrier frequency f ₀ by the information signal a in the transmitting terminal (A). [B] shows the spatially synthesized wave (a1 + b1 + c1) of the spread spectrum modulated wave transmitted from each transmitting terminal. [C] is a spread code p for demodulating the spatially synthesized wave received by the demodulation terminal (D).
₁ shows a demodulated first-order modulated wave subjected to correlation demodulation at ₁ (t). [D] shows the MSK modulated wave, the disturbing wave b3, and the disturbing wave c3 of the information signal a obtained by filtering the demodulated primary modulated wave subjected to the correlation demodulation at the demodulating terminal (D).

As described above, since the optical wireless modulator / demodulator has a spreading code unique to the optical wireless modulator / demodulator, a plurality of optical wireless modulator / demodulators, which were not possible under high efficiency driving of LEDs, are code-division multiplexed within a limited space range. It can be used at the same time and in the same frequency band.

FIG. 7 is a diagram for explaining the principle of the optical space multiplexing system of the optical wireless modulator / demodulator according to the present invention. In FIG. 7, when a plurality of optical wireless modem terminals exist in a limited space,
The principle of the optical space multiplexing method, in which directivity is given to the optical wireless modulation wave transmitted from the optical wireless modulation terminal (transmission terminal) so that multiple optical wireless modulation / demodulation terminals can be multiplexed without causing interference as much as possible. Is shown.

The optical wireless modulated wave transmitted from the transmitting terminal (A) gives directivity to the demodulating terminal (D), and similarly, the transmitting terminal (B) is to the demodulating terminal (E) and the transmitting terminal (C) is to the demodulating terminal. (F) West configuration is given.

As described above, since the optical wireless modulator / demodulator is provided with the optical wireless light emitting means having directivity in the optical wireless modulator, a multiplexing system having both code division multiplexing and optical space division multiplexing can be performed, and a limited space is available. More optical wireless modems can be used within. Further, when an individual terminal moves like a mobile terminal, it is necessary to adjust the directivity of each optical wireless modulator, which makes it difficult to maintain an ideal state. And the code division multiplexing method according to the first aspect, the reliability of transmission and reception can be improved, and the number of multiplexed signals can be dramatically improved.

The above embodiment is an example of the present invention, and the present invention is not limited to the above embodiment.

[0051]

As described above, in the optical wireless modulator / demodulator according to the first aspect of the present invention, the optical wireless modulator / demodulator has different spreading codes, has a code division multiplexing function, and is capable of driving LEDs with high efficiency. Since it is possible to use multiple optical wireless modulators / demodulators in the limited space range at the same time and in the same frequency band as code division multiplexing, and because communication can be performed at low power density, confidentiality, It is possible to provide an optical wireless modulation / demodulation device that has excellent confidentiality, facilitates securing a plurality of channels, has a high interference rejection capability, and can perform stable reception and demodulation.

An optical wireless modulator / demodulator according to a second aspect of the present invention is provided with a plurality of optical wireless modulators provided with optical wireless light emitting means having directivity, and is capable of a multiplexing system having both code division multiplexing and optical space division multiplexing. Since a larger number of optical wireless modulator / demodulators can be used in a space, it is possible to provide an optical wireless modulator / demodulator that is economical, has a large number of multiplexes, is highly reliable in transmission / reception, and has good operability. .

An optical wireless modulator according to a third aspect of the present invention comprises a spread spectrum modulating means for outputting a spread spectrum modulated wave obtained by spread spectrum modulating an information signal, and a driving means for outputting a drive signal based on the spread spectrum modulated wave. A light emitting means for converting the drive signal into an optical signal and transmitting the optical signal as an optical wireless modulated wave; and the spread spectrum modulating means for outputting an information modulating means for outputting a primary modulated wave. Frequency dividing means for dividing the primary modulated wave to output a clock signal, spreading code generating means for generating a spreading code based on the clock signal and outputting the spreading code, primary modulated wave and spreading code And a multiplying means for outputting a spread spectrum modulated wave multiplied by, and capable of stable and stable transmission against interference due to unnecessary radiation from electric equipment and the like. Since the density is low, the influence on other electric devices can be reduced, and since communication can be performed at low power density, an optical wireless modulator / demodulator with excellent confidentiality and concealment and high interference rejection capability is provided. can do.

An optical wireless demodulation device according to a fourth aspect of the present invention demodulates a light receiving means for receiving the optical wireless modulated wave and converting it into an electric signal, and a spread spectrum modulated wave obtained by passing the output of the light receiving means through a bandpass filter. Despread demodulation means for performing despread demodulation by multiplication using the spreading code for use to output a despread demodulation signal, a despread demodulation signal for a primary modulated wave obtained through a bandpass filter, and an amplification means. And a primary demodulation unit including a phase comparison unit, a loop filter, and a voltage controlled oscillation unit for performing primary demodulation and outputting an information signal, and a sliding correlation signal is generated and output to the despreading demodulation unit. Oscillation means for sliding correlation, frequency division means for dividing the primary modulated wave to output a clock signal, synchronization control means for binarizing the output signal of the phase comparison means and outputting a switching signal, and switching Switching means for switching between the sliding correlation signal and the clock signal based on the signal, the spreading code generating means for outputting the demodulation spreading signal based on the clock signal, and the multiplication of the spread spectrum modulated wave and the demodulation spreading signal. , Which outputs a despread demodulation signal, and is capable of strong and stable reception against interference due to unwanted radiation from electrical equipment, etc. A device can be provided.

An optical wireless modulator according to a fifth aspect of the present invention uses synchronous spread modulation in which the primary modulated wave input to the multiplication means and the clock signal input to the spread code generation means are synchronized, and has a simple structure. Since the optical wireless modulator can be put into practical use by a simple circuit operation, it is possible to provide an optical wireless modulator / demodulator which is economical, small-sized, and easy to operate.

An optical wireless demodulation device according to a sixth aspect of the invention is a synchronous despread demodulation in which a spread spectrum modulated wave input to a multiplication means and a clock signal input to a spread code generation means are synchronized, and has a simple structure. Since the optical wireless demodulation device can be put to practical use with a simple circuit operation, it is possible to provide an optical wireless modulation / demodulation device that is economical, small-sized, and has good operability.

[Brief description of the drawings]

FIG. 1 is a block diagram of a main part of an optical wireless modulator according to the present invention.

FIG. 2 is a first-order modulated wave M of the optical wireless modulator according to the present invention.
(T), frequency spectrum diagram of spread spectrum modulated wave SM (t)

FIG. 3 is a block diagram of a main part of an optical wireless demodulation device according to the present invention.

FIG. 4 is an operation explanatory diagram of initial synchronization acquisition of the optical wireless demodulation device according to the present invention.

FIG. 5 is a schematic explanatory diagram of a code division multiplexing system of an optical wireless modulator / demodulator according to the present invention.

FIG. 6 is an explanatory view of the principle of the code division multiplexing system of the optical wireless modulator / demodulator according to the present invention.

FIG. 7 is an explanatory diagram of the principle of the optical space multiplexing method of the optical wireless modulator / demodulator according to the present invention.

FIG. 8 is a block diagram of a main part of an optical wireless modulator of an optical remote controller (optical remote controller).

FIG. 9 is a block diagram of a main part of an optical wireless demodulation device of an optical remote control device (optical remote control device).

FIG. 10: Unwanted radiation characteristics of high-frequency fluorescent lamps used in offices and homes

FIG. 11 is a frequency spectrum characteristic of an optical wireless modulated wave of the optical wireless modulator.

[Explanation of symbols]

1 ... Optical wireless modulation device, 2 ... Optical wireless demodulation device, 10 ... Spread spectrum modulation means, 11 ... Information modulation means, 12, 25
... frequency dividing means, 13 ... spreading code generating means, 14 ... multiplying means, 15 ... driving means, 16 ... light emitting means, 20 ... light receiving means, 21 ... despreading demodulating means, 22, 29, 33 ... bandpass filter, 23 ... multiplication means, 24 ... sliding correlation oscillation means, 26 ... synchronization control means, 27 ... switching means, 28 ... spreading code generation means, 30 ... amplitude limiting amplification means, 31 ... primary demodulation means, 31A ... phase comparison means , 31
B ... Loop filter, 31C ... Voltage controlled oscillation means, 32
... low-pass filter, D (t) ... information signal, DBM ... double balanced mixer, D _E (t) ... error signal, D
_EN (t) ... Demodulation correlation noise component, f ₀ ... Carrier frequency, G
(T) ... Sliding correlation signal, G _C (t) ... Clock signal, M (t) ... Primary modulated wave, M _D1 (t) ... Demodulation 1
Order modulation wave, M _DC (t) ... oscillation output signal, M _DF (t) ... a clock signal, M _F (t) ... a clock signal, p (t) ... spreading code, p _D (t) ... spreading codes, S _C (t) ... light modulated radio _{wave, S D (t), S} D1 (t), S M (t) ... spread spectrum modulated wave, S _M1 (t) ... drive signal, S _W (t) ... switching signal .

Claims (6)

[Claims] 1. An optical wireless modulator, wherein the spread spectrum modulating means outputs a spread spectrum modulated wave by spread spectrum modulating an information signal, a driving means outputting a drive signal based on the spread spectrum modulated wave, and The optical wireless demodulation device includes a light receiving means for receiving the optical wireless modulated wave and converting the optical wireless modulated wave into an electric signal, and a light emitting means for converting the drive signal into an optical signal. Despreading demodulation means for despreading demodulating the output signal to output a despreading demodulated signal,
A demodulation unit that demodulates the despread demodulation signal and outputs an information signal. An optical wireless modulation and demodulation device including the optical wireless modulation device and the optical wireless demodulation device, wherein a plurality of the optical wireless devices are provided. In a system including a modulator / demodulator, the plurality of optical wireless modulators / demodulators each have a different spreading code and have a code division multiplexing function. 2. The optical wireless system according to claim 1, wherein, in the system including a plurality of the optical wireless modulation / demodulation devices, the plurality of the optical wireless modulation devices include optical wireless light emitting means having directivity. Modulator / demodulator. 3. An optical wireless modulator, wherein the spread spectrum modulating means spread spectrum modulates an information signal to output a spread spectrum modulated wave, a driving means outputting a drive signal based on the spread spectrum modulated wave, and And a light emitting means for converting the drive signal into an optical signal and transmitting an optical wireless modulated wave, wherein the spread spectrum modulating means modulates the information signal to
Information modulating means for outputting a next modulated wave, frequency dividing means for dividing the primary modulated wave to output a clock signal, and spread code generating means for generating and outputting a spread code based on the clock signal. Multiplication means for multiplying the primary modulated wave and the spread code to output the spread spectrum modulated wave,
An optical wireless modulator, comprising: 4. An optical wireless demodulation device, a light receiving means for receiving an optical wireless modulated wave and converting it into an electric signal, and an output signal of the light receiving means is despread demodulated by using a demodulating spreading code to perform despread demodulation. Despreading demodulation means for outputting a signal, and primary demodulation means for primary demodulating the despread demodulation signal and outputting an information signal, the primary demodulation means comprising a phase comparison means, a loop filter, and a voltage controlled oscillation means, The despreading demodulation means includes a sliding correlation oscillating means for generating and outputting a sliding correlation signal, a frequency dividing means for dividing the primary modulated wave and outputting a clock signal, and an output signal of the phase comparing means. Synchronization control means for binarizing and outputting a switching signal, switching means for switching the sliding correlation signal and the clock signal based on the switching signal, and the demodulation based on the clock signal. An optical wireless system comprising: spreading code generating means for outputting a spread signal; and multiplying means for multiplying the spread spectrum modulated wave by the demodulating spread signal to output a despread demodulated signal. Demodulator. 5. The optical wireless modulation device is a synchronous spread modulation in which a primary modulated wave input to the multiplication means and a clock signal input to the spread code generation means are synchronized. An optical wireless modulator according to claim 1, 2, or 3. 6. The optical wireless demodulation device is a synchronous despread demodulation in which a spread spectrum modulated wave input to the multiplication means and a clock signal input to the spread code generation means are synchronized. 5. The optical wireless demodulation device according to claim 1, 2, or 4.