JP2013254996A - Transmitter, mobile body mounted with the same, and signal processing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a transmitter, a mobile body mounted therewith and a signal processing device which perform bandpass ΔΣ modulation on a modulated wave of a desired carrier frequency.SOLUTION: A transmitter 1 includes: a bandpass ΔΣ modulator 25 for performing ΔΣ modulation on a digital RF signal with a transmission signal added to a carrier; a transmission section for transmitting a quantized signal output from the ΔΣ modulator 25; and a control section 35 for controlling the bandpass ΔΣ modulator 25 such that the frequency band of the digital RF signal is included in a quantization noise stopband of the ΔΣ modulation performed by the bandpass ΔΣ modulator 25.

Description

  The present invention relates to a transmitter, a mobile body equipped with the transmitter, and a signal processing device.

ΔΣ modulation is a type of oversampling modulation, and is generally a technique used for AD conversion or DA conversion, and is used for signal transmission or the like (see Non-Patent Document 1).
In ΔΣ modulation, noise shaping (Noise Shaping) is performed in which the quantization noise in the signal band is moved outside the signal band to greatly reduce the quantization noise in the signal band.

Here, the term “ΔΣ modulation” often refers to low-pass type ΔΣ modulation.
In the low-pass ΔΣ modulation, low-frequency quantization noise is moved to a higher frequency side, and noise shaping is performed so that the low-frequency quantization noise is attenuated. That is, in the low-pass type Δ modulation, the noise transfer function has a characteristic of blocking passing noise at a low frequency (near 0 Hz).

  In addition to the low-pass type ΔΣ modulation, there is also a band-pass type ΔΣ modulation in which a noise transfer function blocks a passing noise at a frequency larger than 0 Hz.

Takao Wabo, Akira Yasuda (original author Richard Schreier, Gabor C. Temes) Introduction to ΔΣ analog / digital converters (Understanding Delta-Sigma Data Converters), Maruzen Co., Ltd., 2007, pp1-17

According to Non-Patent Document 1, by performing z → −z ² conversion on the z-region model of the low-pass ΔΣ modulator, the low-pass ΔΣ modulator can be converted into a bandpass ΔΣ modulator.

However, even if the conversion formula z → −z ² is used, an fs / 4 bandpass ΔΣ modulator that operates at a frequency that is ¼ of the sampling frequency fs (the center frequency f ₀ of the quantization noise stop band is fs / Only a bandpass type ΔΣ modulator 4).
That is, the bandpass ΔΣ modulator obtained by using the z → −z ² conversion formula is limited to the one in which the center frequency f ₀ of the band of the signal to be processed is ¼ of the sampling frequency fs. It is done.

Non-Patent Document 1 does not disclose the structure of a bandpass type ΔΣ modulator for frequency f ₀ other than a quarter of the sampling frequency fs.
For this reason, for example, even if a bandpass ΔΣ modulator is used to transmit a radio frequency carrier wave, the bandpass ΔΣ modulator limits the frequency to be processed as described above. The signal transmission at the carrier frequency cannot be performed.

  The present invention has been made in view of such circumstances, and provides a transmitter capable of performing bandpass ΔΣ modulation on a modulated wave having a desired carrier frequency, and a moving body and a signal processing device equipped with the transmitter. The purpose is to do.

(1) The present invention for achieving the above object is a transmitter for transmitting a modulated wave in which a transmission signal is added to a carrier wave, and performs a bandpass type ΔΣ modulation on the modulated wave. A modulator, a transmission unit that transmits a quantized signal output from the bandpass ΔΣ modulator, and a frequency band of the modulated wave is a quantization noise blocking band of ΔΣ modulation performed by the bandpass ΔΣ modulator. And a control unit that controls the band-pass ΔΣ modulator.

According to the transmitter having the above configuration, the control unit controls the bandpass ΔΣ modulator so that the frequency band of the modulated wave is included in the quantization noise rejection band of ΔΣ modulation. In addition, bandpass ΔΣ modulation can be performed.
Further, according to the transmitter of the present invention, the control unit controls the bandpass ΔΣ modulator so that the frequency band of the modulated wave is included in the quantization noise blocking band of ΔΣ modulation. A modulated wave can be extracted from the quantized signal output from the ΔΣ modulator and transmitted without frequency conversion.

(2) (3) In the transmitter, the transmission signal is preferably a radio frequency modulated wave.
Moreover, it is preferable that the said control part is further provided with the function to determine the frequency of the said carrier wave. In this case, the determination of the frequency of the carrier wave and the control of the center frequency of the quantization noise stopband of ΔΣ modulation corresponding to this can be performed collectively by the control unit.

(4) It is preferable that the frequency of the carrier wave is set within a sampling frequency range of the band-pass ΔΣ modulator.

(5) When the frequency of the carrier wave is recognized by a third party, communication secrecy such as communication interception is significantly reduced. For this reason, the transmitter may further include a volatile storage unit, and the storage unit may be configured to store frequency information indicating the frequency of the carrier wave.
In this case, when the power supplied to the storage unit is cut off, the stored frequency information is erased. For example, it is possible to prevent the frequency information from being recognized as much as possible by reverse engineering, and the confidentiality of the communication can be reduced. Can be maintained.

(6) In the transmitter, it is preferable that the control unit further includes a function of determining the frequency of the carrier wave by frequency hopping from a plurality of predetermined frequencies.
In the transmitter, the transmission unit can extract and transmit the modulated wave from the quantized signal output from the ΔΣ modulator without frequency conversion, so that the control unit determines the frequency of the carrier to determine the setting. The degree of freedom is increased. Thereby, the plurality of frequency information can be set from a wider range. As a result, for example, the carrier frequency can be spread over a wider band than in the case of using a VCO whose setting bandwidth is limited for setting the carrier frequency, and has high fault tolerance and communication. Frequency hopping with excellent secrecy can be realized.

(7) Further, in the case where the storage unit is configured to be capable of storing the plurality of frequency information and pattern information related to a hopping pattern of frequency hopping, the control unit is configured to store the storage unit in the storage unit. The frequency of the carrier wave may be determined by referring to a plurality of frequency information and the pattern information.
Also in this case, as described above, when the power supplied to the storage unit is cut off, a plurality of stored frequency information and hopping patterns are erased, so that the confidentiality of communication can be maintained.

(8) Moreover, this invention is a movable mobile body provided with the transmission part which transmits information, Comprising: The said transmission part is a transmitter as described in said (1)-(7), It is characterized by the above-mentioned. It is said.
(9) The signal processing device according to the present invention includes a bandpass ΔΣ modulator that performs bandpass ΔΣ modulation on a modulated wave with a transmission signal added to a carrier wave, and the frequency band of the modulated wave is And a control unit that controls the band-pass ΔΣ modulator so as to be included in the quantization noise rejection band of ΔΣ modulation performed by the band-pass ΔΣ modulator.
According to the mobile body and the signal processing apparatus having the above-described configuration, bandpass ΔΣ modulation can be performed on a modulated wave having a desired carrier frequency in information transmission.

  According to the present invention, bandpass ΔΣ modulation can be performed on a modulated wave having a desired carrier frequency.

It is a block diagram which shows the transmitting apparatus which concerns on one Embodiment of this invention. It is a block diagram of a ΔΣ modulator. This is a primary low-pass type ΔΣ modulator. This is a secondary band-pass ΔΣ modulator obtained by converting from a primary low-pass ΔΣ modulator. It is a figure for demonstrating the frequency conversion function of the signal in a modulation process part. (A) is an example of a waveform diagram of a frequency spectrum of an output from a ΔΣ modulator when frequency hopping is applied, and (b) is an enlarged view of a band in the vicinity of a carrier frequency in (a). It is a figure which shows the airplane which mounts the transmitter of this embodiment and can be controlled by remote control. It is a block diagram which shows the structure of the radio | wireless transmitter using VCO.

  Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings.

[1. System configuration]
FIG. 1 is a block diagram showing a transmitter 1 according to an embodiment of the present invention. The transmitter 1 includes a digital signal processing unit 21, an analog filter 32, an amplifier 33 connected to the analog filter 32, and a transmission antenna 34 connected to the output terminal of the amplifier 33.

  The digital signal processing unit 21 outputs a digital signal (1-bit quantized signal: 1-bit pulse train) representing an RF (Radio Frequency) signal that is an analog signal (modulated wave) of a band transmission method using a carrier wave. The RF signal is a transmission signal to be radiated into the space as a radio wave, for example, an RF signal for mobile communication and an RF signal for broadcasting services such as television / radio.

An output from the digital signal processing unit 21 is given to an analog filter (bandpass filter or lowpass filter) 32. The analog signal expressed by the 1-bit pulse train includes noise components other than the RF signal. The noise component is removed by the analog filter 32.
The 1-bit pulse train simply passes through the analog filter 32 and becomes a pure analog signal.
The analog RF signal output from the analog filter 32 is given to the transmitting antenna 34 and radiated to the space. Note that the transmission antenna 34 may have a function as the analog filter 32.

Whether the analog filter 32 is a band-pass filter or a low-pass filter is appropriately determined depending on the frequency of the RF signal.
When the digital signal processing unit 21 performs signal conversion by band-pass ΔΣ modulation, a band-pass filter is used as the analog filter 32. When the digital signal processing unit 21 performs signal conversion by low-pass ΔΣ modulation, the analog filter 32 is used. A low-pass filter is used.

  The signal transmission path 4 between the digital signal processing unit 21 and the analog filter 32 may be a signal wiring formed on a circuit board, or a transmission line such as an optical fiber or an electric cable. The signal transmission path 4 does not have to be a dedicated line for transmitting a 1-bit pulse train, and may be a communication network that performs packet communication such as the Internet. When a communication network that performs packet communication is used as the signal transmission path 4, the transmission side (digital signal processing unit 21 side) converts a 1-bit pulse string into a bit string, transmits it to the signal transmission path 4, and receives it on the reception side (analog filter). 32 side) may restore the received bit string to the original 1-bit pulse string.

  The digital signal processing unit 21 can be regarded as a transmitter that transmits a 1-bit pulse train to the signal transmission path 4. In this case, the device having the analog filter 32 can be regarded as a receiver of the RF signal.

  The digital signal processing unit 21 includes a baseband unit 23 that outputs a baseband signal (IQ signal) that is a transmission signal, a processing unit 24 that modulates the baseband signal, a ΔΣ modulator 25, a control unit 35, And a storage unit 36.

The baseband unit 23 outputs IQ baseband signals (I signal and Q signal) as digital data.
The processing unit 24 performs processing such as digital quadrature modulation on the IQ baseband signal. Therefore, the processing unit 24 outputs a signal in a digital signal format expressed by multi-bit digital data (discrete values).
The modulation in the processing unit 24 is not limited to quadrature modulation, and may be modulation of another method for generating a modulated wave.
The processing unit 24 performs various digital signal processing such as DPD (Digital Pre-distortion), CFR (Crest Factor Reduction), and DUC (Digital Up Conversion) in addition to quadrature modulation. The processing unit 24 outputs an RF signal generated by various digital signal processing as described above.

The processor 24 superimposes (adds) the IQ baseband signal on a carrier wave when orthogonally modulating the IQ baseband signal. The carrier frequency f _{0 at} this time is based on the control of the control unit 35 as described later. Is set. That is, the processing unit 24 outputs a digital RF signal having a carrier frequency f ₀ .

In the present embodiment, the processing unit 24 performs frequency conversion to the carrier frequency f ₀ , but a frequency conversion unit for converting the signal frequency between the processing unit 24 and the ΔΣ modulator 25. It is good also as a structure which provides. In this case, the processing unit 24 generates a digital signal of a predetermined intermediate frequency, the frequency conversion section performs frequency conversion of the intermediate frequency of the digital signal based on the control of the control unit 35, the digital carrier frequency f ₀ RF signal is output.

  The digital RF signal output from the processing unit 24 is given to a bandpass ΔΣ modulator (converter 25). Note that the converter 25 may be a low-pass type ΔΣ modulator or a PWM modulator.

The ΔΣ modulator 25 performs ΔΣ modulation on the input RF signal and outputs a 1-bit quantized signal (1-bit pulse train). The 1-bit pulse train output from the ΔΣ modulator 25 is a digital signal, but represents an analog RF signal.
The 1-bit pulse train output from the ΔΣ modulator 25 is output from the digital signal processing unit 21 to the signal transmission path 4 as an output signal of the digital signal processing unit 21.

When the quantized signal output from the ΔΣ modulator 25 is applied to the analog filter 32 through the signal transmission path 4, the analog filter 32 outputs an analog RF signal.
The analog RF signal output from the analog filter 32 reaches the transmitting antenna 34 via the amplifier 33 and is radiated.
Therefore, the analog filter 32, the amplifier 33, and the transmission antenna 34 constitute a transmission unit that transmits the quantized signal output from the ΔΣ modulator 25 as an analog RF signal.

The control unit 35 has a control function such as carrier wave frequency control described later, and controls each unit in the digital signal processing unit 21 and the analog filter 32.
The storage unit 36 is accessible by the control unit 35, the processing unit 24, the ΔΣ modulator 25, and the analog filter 32. The storage unit 36 is configured to be able to store information necessary for controlling the carrier frequency described later.
The functions of the control unit 35 and the storage unit 36 will be described in detail later.

[2. About ΔΣ modulator]
As shown in FIG. 2, the ΔΣ modulator 25 includes a loop filter 27 and a quantizer 28 (see Non-Patent Document 1).
In the ΔΣ modulator 25 shown in FIG. 2, an input U (RF signal in the present embodiment) U is given to the loop filter 27. The output Y of the loop filter 27 is given to a quantizer (1 bit quantizer) 28. The output (quantized signal) V of the quantizer 28 is given as another input to the loop filter 27.

The characteristic of the delta-sigma modulator 25 can be represented by a signal transfer function (STF) and a noise transfer function (NTF; Noise Transfer Function).
That is, when the input of the ΔΣ modulator 25 is U, the output of the ΔΣ modulator 25 is V, and the quantization noise is E, the characteristics of the ΔΣ modulator 25 are expressed in the z region as follows. is there.

  Therefore, given the desired NTF and STF, the transfer function of the loop filter 27 can be obtained.

FIG. 3 shows a block diagram of the linear z-domain model of the first-order low-pass ΔΣ modulator 125. Reference numeral 127 represents a loop filter portion, and reference numeral 128 represents a quantizer. When the input to the ΔΣ modulator 125 is U (z), the output is V (z), and the quantization noise is E (z), the characteristics of the ΔΣ modulator 125 are expressed in the z region. It is as follows.
V (z) = U (z) + (1-z ⁻¹ ) E (z)

That is, in the first-order low-pass ΔΣ modulator 125 shown in FIG. 3, the signal transfer function STF (z) = 1 and the noise transfer function NTF (z) = 1−z ⁻¹ .

According to Non-Patent Document 1, a low pass type ΔΣ modulator can be converted into a band pass type ΔΣ modulator by performing the following conversion on the low pass type ΔΣ modulator.

By replacing z in the z region model of the low-pass ΔΣ modulator 125 with z ′ = − z ² in accordance with the above conversion formula, a band-pass ΔΣ modulator can be obtained.

  Using the above conversion equation, an n-order low-pass ΔΣ modulator (n is an integer of 1 or more) can be converted to a 2n-order band-pass Σ modulator.

The inventor has found a conversion formula for obtaining a bandpass type ΔΣ modulator having a desired frequency f ₀ (θ = θ ₀ ) as a center frequency f ₀ from a low pass type ΔΣ modulator. The conversion formula is as shown in the following formula (3), for example.

here,
θ ₀ = 2π × (f ₀ / fs) fs is the sampling frequency of the ΔΣ modulator.

The conversion formula of Formula (2) relates to a specific frequency θ ₀ = π / 2, but the conversion formula of Formula (3) is generalized to an arbitrary frequency (θ ₀ ).

FIG. 4 shows a second-order band-pass ΔΣ modulator 25 obtained by converting the first-order low-pass ΔΣ modulator 125 shown in FIG. 3 using the conversion equation (3).
In the conversion from FIG. 3 to FIG. 4, for the convenience of notation, the following conversion equation with a = cos θ ₀ in Equation (3) was used.

  The conversion to the band-pass type ΔΣ modulator can be applied to other high-order low-pass type ΔΣ modulators (for example, the CIFB structure, the CRFF structure, the CIFF structure, etc. described in Non-Patent Document 1).

  The ΔΣ modulator 25 can convert the value of z based on the above equation (3). That is, the ΔΣ modulator 25 can change the center frequency of the quantization noise stop band. In other words, the quantization noise stop band can be changed.

The control unit 35 converts z of the ΔΣ modulator 25 based on the above-described equation (3) according to the center frequency of the signal input to the ΔΣ modulator 25 (carrier frequency f ₀ of the digital RF signal). Thus, band-pass ΔΣ modulation can be performed on a signal having an arbitrary frequency.
In this manner, by changing cos θ ₀ (coefficient a) in the above conversion equation (3) according to the carrier frequency f ₀ of the RF signal, it corresponds to an arbitrary frequency f ₀ without changing the sampling frequency fs. Bandpass ΔΣ modulation can be performed. When cos θ ₀ is changed, the coefficient of NTF shown in Expression (1) is changed, but the order of the expression is maintained. Therefore, even if the configuration of the bandpass ΔΣ modulator 25 is changed in accordance with the carrier frequency f ₀ of the RF signal, the complexity (order) of the equation does not change. Therefore, the bandpass ΔΣ modulator 25 is not changed. The signal processing load in the case does not change.

As described above, the present embodiment is advantageous because the signal processing load in the band-pass ΔΣ modulator 25 does not change even when the carrier frequency f ₀ is changed. In the present embodiment, the signal processing load in the band-pass ΔΣ modulator 25 depends on the sampling frequency fs determined by the signal bandwidth according to the Nyquist theorem, but the signal bandwidth even when the carrier frequency f ₀ is changed. Therefore, it is not necessary to change the sampling frequency fs. When the ΔΣ modulator is a low-pass type, it is necessary to change the sampling frequency fs in order to cope with a change in the carrier frequency f ₀ , and in this respect, the band-pass type is advantageous.

Further, by using the expression (3), the ΔΣ modulator 25 can be used not only as a bandpass type ΔΣ modulator that can cope with an arbitrary frequency (f ₀ ) but also as a low pass type ΔΣ modulator. That is, the ΔΣ modulator 25 can be switched between a low pass type and a band pass type.

  As described above, the control unit 35 and the bandpass ΔΣ modulator 25 constitute a signal processing device that can perform bandpass ΔΣ modulation on a modulated wave having a desired carrier frequency.

[3. Control of carrier frequency]
As described above, the control unit 35 has the function of changing and controlling the center frequency of the quantization noise stop band by the ΔΣ modulator 25, and the function of controlling the center frequency and pass band of the analog filter 32. Also have.
The control unit 35 has a function of determining the carrier frequency f ₀ and controlling the processing unit 24 to adjust the carrier frequency f ₀ of the digital RF signal output from the processing unit 24.

The storage unit 36 stores frequency information that is information indicating the carrier frequency f ₀ determined by the control unit 35.
The control unit 35 causes the processing unit 24 to refer to the storage unit 36 and obtains frequency information indicating the carrier frequency f ₀ determined by the control unit 35. When the processing unit 24 acquires frequency information indicating the carrier frequency f ₀ from the storage unit 36, the processing unit 24 performs orthogonal modulation based on the frequency information.

FIG. 5 is a diagram for explaining functions related to quadrature modulation of the IQ baseband signal in the processing unit 24. As shown in FIG, IQ baseband signal processing section 24 is given the multiplication a first multiplier 24a for multiplying the cosine wave of the carrier frequency f ₀ to the I component, the sine wave of the carrier frequency f ₀ to the Q component A second multiplier 24b, and an adder 24c that adds these two components.
The processor 24 outputs a digital RF signal having a carrier frequency f ₀ by superimposing a signal wave having a carrier frequency f ₀ for each component of the IQ baseband signal during quadrature modulation.
As described above, the control unit 35 controls the processing unit 24 and sets the carrier frequency f ₀ of the digital RF signal output from the processing unit 24.

Further, the control unit 35 causes the ΔΣ modulator 25 to refer to the storage unit 36 to acquire frequency information indicating the carrier frequency f ₀ set by the control unit 35, and the frequency band of the RF signal having the carrier frequency f ₀ Is controlled to be included in the quantization noise stop band of ΔΣ modulation.
ΔΣ modulator 25 obtains the frequency information from the storage unit 36, the center frequency of the quantization noise stop band is adjusted so that the carrier frequency f _0. As a result, the RF signal having the carrier frequency f ₀ is included in the quantization noise stop band of ΔΣ modulation of the ΔΣ modulator 25.
Control unit 35, the analog filter 32, similar to the ΔΣ modulator 25, by referring to the storage unit 36, controlled by obtaining the frequency information indicating the carrier frequency f ₀ of the control unit 35 has set.

Referring to FIG. 1, when determining the carrier frequency f ₀ , the control unit 35 controls the processing unit 24, the ΔΣ modulator 25, and the analog filter 32 to execute processing based on the determined carrier frequency f ₀ . .
That is, the control unit 35, based on the carrier frequency f ₀ determined, RF signal processing unit 24 outputs is adjusted to be the carrier frequency f _0. Further, the control unit 35 adjusts so that the center frequency of the quantization noise stop band in the ΔΣ modulator 25 becomes the carrier frequency f ₀ . Further, the control unit 35 adjusts the center frequency and pass band of the analog filter 32 so that the RF signal having the carrier frequency f ₀ can be extracted.

As described above, the control unit 35 determines the carrier frequency f ₀ to a desired value, and controls the processing unit 24, the ΔΣ modulator 25, and the analog filter 32 based on the determined carrier frequency f ₀ . An RF signal having an arbitrary carrier frequency can be transmitted from the antenna 34.

According to the transmitter 1 having the above configuration, the control unit 35 controls the ΔΣ modulator 25 so that the RF signal having the carrier frequency f ₀ is included in the quantization noise stop band of ΔΣ modulation. It is possible to perform bandpass ΔΣ modulation on the RF signal as the modulated wave.

Here, a transmitter that transmits an RF signal generally generates a radio frequency carrier wave using a VCO (Voltage Controlled Oscilator).
FIG. 8 is a block diagram showing a configuration of a wireless transmitter using a VCO. This transmitter includes a digital signal processing unit 100 for digitally processing a baseband signal. The digital signal output from the digital signal processing unit 100 is converted into an analog signal by the digital / analog converter 101. The converted analog signal is frequency-converted by superimposing a carrier wave supplied by a VCO (Voltage Controlled Oscilator) 102. The frequency-converted analog signal is amplified by the amplifier 103 as an RF signal and radiated from the antenna 104 to the space.
When a VCO is used to obtain an RF signal as in the transmitter described above, the frequency band that can be used as a carrier frequency is limited to a frequency that can be oscillated by the VCO.

In this regard, according to the transmitter 1 of the present embodiment, the control unit 35 controls the ΔΣ modulator 25 so that the RF signal having the carrier frequency f ₀ is included in the quantization noise rejection band of ΔΣ modulation. The analog filter 32 and the transmitting antenna 34 connected to the subsequent stage as the transmitting unit can extract and transmit the RF signal from the quantized signal from the ΔΣ modulator without performing frequency conversion. Therefore, it is not necessary to use VCO, it is possible to increase the degree of freedom in setting of the carrier frequency f _0.
That is, the transmitter 1 according to the present embodiment generates an RF signal having the carrier frequency f ₀ by digital processing by the digital signal processing unit 21 and transmits the generated RF signal without frequency conversion, and thus needs to use a VCO. Absent. Consequently, without being limited to capable of oscillating frequency by VCO, it is possible to increase the degree of freedom in setting of the carrier frequency f _0.

The control unit 35 of the present embodiment is provided with the function of determining the carrier frequency f _0, the determination of the carrier frequency f _0, and a band-pass type ΔΣ modulation of the quantization noise rejection band corresponding to The control of the center frequency can be performed collectively by the control unit.

[4. About frequency hopping]
The transmitter 1 of the present embodiment has a function of determining the carrier frequency f ₀ by frequency hopping.
Control unit 35, in order to determine the carrier frequency f _0, which refers to the information stored in the storage unit 36.
As illustrated in FIG. 1, the storage unit 36 includes a plurality of frequency information as information necessary for determining the carrier frequency f ₀ , and a hopping pattern when performing frequency hopping using the plurality of frequency information. Is remembered.

A plurality of frequency information is information indicating a carrier frequency f ₀ which is determined in advance in order to sequentially change when applying the frequency hopping. A plurality of frequency information, transmitter 1 from a settable frequency range as the carrier frequency f _0, is set to be different frequencies.
The control unit 35 selects and determines one frequency information from among a plurality of frequency information as the carrier frequency f ₀ and controls the processing unit 24, the ΔΣ modulator 25, and the analog filter 32 to execute frequency hopping. To do.

The hopping pattern is a plurality of frequency information registered in association with a pattern for selecting a plurality of frequency information to be sequentially changed when applying frequency hopping.
When determining the carrier frequency f ₀ , the control unit 35 refers to the hopping pattern stored in the storage unit 36. Control unit 35, based on a hopping pattern, selects one of the frequency information from a plurality of frequency information, determines the carrier frequency f _0.
Control unit 35 sequentially performs the determination of the carrier frequency f ₀ according to a hopping pattern. As a result, the transmitter 1 transmits a transmission signal to which frequency hopping is applied.

The plurality of frequency information and hopping patterns are determined in advance and are shared with the receiver that receives the transmission signal from the transmitter 1.
By sharing a plurality of frequency information and hopping patterns, the receiver can receive a transmission signal to which frequency hopping transmitted by the transmitter 1 is applied.

As described above, the transmitter 1 of this embodiment can adjust the carrier frequency f ₀ without using a VCO. Therefore, the carrier frequency f ₀ is not limited to a frequency range that can be oscillated by the VCO.
Since the upper limit of the signal frequency that can be oscillated by the VCO is generally about 5 GHz, the conventional transmitter needs to set frequency information for hopping within a band of about 5 GHz.

On the other hand, in the transmitter 1 of this embodiment, the quantized signal output from the digital signal processing unit 21 is radiated as an RF signal via the analog filter 32, the antenna 34, and the like without frequency conversion without using a VCO. .
The carrier frequency f ₀ of the radiated RF signal is adjusted by digital processing by the processing unit 24 included in the digital signal processing unit 21.
Therefore, the carrier frequency f ₀ can be adjusted within a frequency range that the digital signal processing unit 21 can generate. The frequency that can be generated by the digital circuit constituting the digital signal processing unit 21 is higher than about 5 GHz, which is a general upper limit of the VCO, and the carrier frequency f ₀ is in a wider range than when the VCO is used. Can be set.

However, the carrier frequency f ₀ indicated by the frequency information is set within the range of the sampling frequency fs of the ΔΣ modulator 25. This is because if the carrier frequency f ₀ exceeds the sampling frequency fs of the ΔΣ modulator 25, the RF signal obtained from the quantized signal may not be accurately reproduced.

FIG. 6A is an example of a waveform diagram of the frequency spectrum of the output from the ΔΣ modulator 25 when frequency hopping is applied. In the illustrated example, the carrier frequency f ₀ is set to 800 MHz, which is the frequency position indicated by the diamond mark 1 in the figure, within the range of ₀ Hz to 6 GHz. That is, the power peak portion seen at 800 MHz is the frequency of the RF signal on which the signal is superimposed.
In accordance with the carrier frequency f ₀ , the center frequency of the quantization noise stop band of the ΔΣ modulator 25 is also set to 800 MHz. For this reason, portions where the power value is extremely reduced are seen on both sides of the band seen at 800 MHz.
In addition, although the power peak part is seen also in other parts, these are the harmonics of the RF signal superimposed at 800 MHz.

FIG. 6B is an enlarged view of the band near the carrier frequency f ₀ in FIG. In the figure, a signal (RF signal) is superimposed around 800 MHz.
In Figure 6, but the carrier frequency f ₀ of the RF signal was exemplified when set to 800 MHz, can either be set to the carrier frequency f ₀ by using harmonics appearing in FIG. 6 (a), the carrier For example, the frequency f ₀ can be set to an arbitrary frequency within a range up to 6 GHz. Further, when a higher frequency can be generated, it can be set from a wider band than the band shown in FIG.

Thus, by control unit 35 to determine the carrier frequency f ₀ by a frequency hopping, the degree of freedom is increased in setting the carrier frequency f _0, which can be set carrier frequency f ₀ from a wider range of frequency bands, A plurality of frequency information can be set from a wider range. As a result, it is possible to spread the carrier frequency f ₀ over a wider band than in the case of using a VCO in which the setting range of the carrier frequency is limited, and has high fault tolerance and excellent communication confidentiality. Frequency hopping can be realized.
Furthermore, since the carrier frequency f ₀ can be spread over a wider band, even if it is multiplexed, the possibility of overlapping of the bands is low and the use by many users is facilitated.

[5. About other embodiments]
In the above embodiment, the case where the control unit 35 stores a plurality of frequency information and hopping patterns used for frequency hopping application in the storage unit 36 is exemplified. However, the plurality of frequency information and hopping patterns are transmitted to a third party. Once recognized, it is important information that makes it impossible to maintain confidentiality of communication.
Therefore, in order to prevent a plurality of frequency information and hopping patterns from being recognized by a third party, the storage unit 36 is volatile so that the stored information is erased when the power supply is cut off. You may comprise by a memory | storage part. The storage unit 36 is configured to be able to store a plurality of frequency information and hopping patterns.

  When a VCO is used as in the transmitter shown in FIG. 8, since the VCO is an analog circuit, adjustment and setting of hardware including the VCO are necessary to realize frequency hopping. For this reason, there is a possibility that frequency information and a hopping pattern may be recognized by a third party by reverse engineering.

In this regard, in the present embodiment, the digital signal processing unit 21 determines a carrier frequency f ₀ of the RF signal, can be adjusted, the determination and adjustment of the carrier frequency f ₀ of the RF signal in the digital processing It can be carried out.
Therefore, if a plurality of frequency information and hopping patterns are given from the outside and stored as information in the storage unit 36 (FIG. 1), the control unit 35 stores the stored information without adjusting hardware. Based on the frequency hopping can be performed. Even if the storage unit 36 is configured by a volatile storage unit, the control unit 35 can perform frequency hopping in the same manner.

  Here, in this embodiment, since the memory | storage part 36 is comprised by the above-mentioned volatile memory | storage part, even if the transmitter 1 is disassembled by the third party, the power supply of the transmitter 1 stops. If the power supply to the storage unit 36 is cut off, the stored plurality of frequency information and hopping patterns are erased. Thereby, it is possible to prevent a third party from recognizing the frequency information and the hopping pattern by reverse engineering, and it is possible to maintain confidentiality of communication.

  In the transmitter 1 of the above embodiment, if the power supply to the storage unit 36 is cut off, the frequency information and the hopping pattern can be prevented from being recognized by a third party. It can be suitably used when performing secret communication between a passenger who is on a moving body such as an airplane and a person who is located outside the moving body.

In this case, the mobile body includes the transmitter 1 of the above embodiment and a receiver that can receive a transmission signal from the transmitter 1. Moreover, the person located outside the moving body also includes the transmitter 1 and the receiver as in the moving body.
Even if the transmitter 1 mounted on the mobile body is acquired by a third party, if the transmitter 1 is broken and the power supply to the storage unit 36 is cut off, the frequency information and the hopping pattern are It is not recognized by a third party. Therefore, even when the transmitter 1 is acquired by a third party, the confidentiality of communication can be maintained.

Further, when the mobile body is remotely controlled from the outside, the transmitter 1 of the above embodiment can be used as a communication means for transmitting and receiving control information necessary for control.
FIG. 7 is a diagram showing an airplane that is equipped with the transmitter 1 of the embodiment and can be controlled by remote control. In the figure, an airplane 40 is remotely controlled by receiving control information transmitted from, for example, a control device 50 located on the ground.

The airplane 40 includes an operation control unit 41 that controls the operation of the airplane 40, the transmitter 1 of the above-described embodiment, a receiver 42 that receives control information given from the control device 50 as an outside, and an antenna 43. I have.
The control device 50 also includes the transmitter 1 of the above embodiment. Moreover, the receiver which can receive the transmission signal to which the frequency hopping applied from the transmitter 1 of the airplane 40 is applied is provided.

When receiving the control information from the control device 50, the receiver 42 of the airplane 40 gives this control information to the steering control unit 41. The steering control unit 41 performs processing based on the control information and gives response information (for example, the current position of the airplane 40, the speed, the surrounding situation, etc.) to the transmitter 1. The transmitter 1 given the response information transmits the response information to the control device 50 by frequency hopping.
As described above, the airplane 40 is remotely controlled by communicating with the control device 50.

Also in this case, the transmitter 1 mounted on the airplane 40 can perform frequency hopping with improved freedom of setting the carrier frequency f _{0 in} communication with the control device 50 and excellent communication confidentiality. it can.
Further, even if the airplane 40 and the transmitter 1 are acquired by a third party, the frequency information and the hopping pattern can be obtained if the power supply to the storage unit 36 is cut off due to the transmitter 1 being broken or the like. It is not recognized by a third party. Therefore, even when the airplane 40 and the transmitter 1 are acquired by a third party, the confidentiality of communication can be maintained.

A plurality of frequency information and hopping patterns necessary for communication are given to the transmitter 1 as follows. That is, in the transmitter 1 of the airplane 40 at the stage before activation, the volatile storage unit 36 (FIG. 1) does not store a plurality of frequency information and hopping patterns.
When the transmitter 1 is activated to remotely control the airplane 40, first, the storage unit 36 is provided with a plurality of frequency information and hopping patterns necessary for communicating with the control device 50. The storage unit 36 to which a plurality of frequency information and hopping patterns are given stores them. Thereby, the transmitter 1 can communicate with the control device 50 by using the frequency information and the hopping pattern stored in the storage unit 36.

  Thereafter, if the airplane 40 breaks down and the power supply to the storage unit 36 is cut off due to the transmitter 1 being broken or the like, the plurality of frequency information and hopping patterns stored in the storage unit 36 are deleted. In this case, even if power is supplied to the storage unit 36 again, a plurality of frequency information and hopping patterns have been deleted, so even when the airplane 40 and the transmitter 1 are acquired by a third party. Communication confidentiality can be maintained.

  In the above embodiment, the case where the airplane 40 as a moving body is remotely controlled has been exemplified. However, for example, when a missile is launched, it does not return to the original position and is suitable for a moving body with a high probability of breaking. Can be mounted on.

[6. Addendum]
The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the meanings described above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

1 Transmitter 21 Digital Signal Processing Unit 32 Analog Filter 33 Amplifier 34 Transmitting Antenna 24 Modulation Processing Unit 25 Bandpass ΔΣ Modulator 35 Control Unit 36 Storage Unit 40 Airplane (Mobile Object)

(7) In addition, before Symbol plurality of frequency information, and if further comprises storable in the storage unit of the configured volatile pattern information about the hopping pattern of frequency hopping, the control unit, said storage unit The frequency of the carrier wave may be determined by referring to the plurality of frequency information stored in the pattern and the pattern information.
Also in this case, as described above, when the power supplied to the storage unit is cut off, a plurality of stored frequency information and hopping patterns are erased, so that the confidentiality of communication can be maintained.

(8) Further, the present invention provides a movable mobile having a transmitter for transmitting information, said transmitter being a transmitter according to the above (1) to (7) It is said.
(9) The signal processing device according to the present invention includes a bandpass ΔΣ modulator that performs bandpass ΔΣ modulation on a modulated wave with a transmission signal added to a carrier wave, and the frequency band of the modulated wave is And a control unit that controls the band-pass ΔΣ modulator so as to be included in the quantization noise rejection band of ΔΣ modulation performed by the band-pass ΔΣ modulator.
According to the mobile body and the signal processing apparatus having the above-described configuration, bandpass ΔΣ modulation can be performed on a modulated wave having a desired carrier frequency in information transmission.

Claims (9)

A transmitter for transmitting a modulated wave with a transmission signal added to a carrier wave,
A bandpass ΔΣ modulator that performs bandpass ΔΣ modulation on the modulated wave;
A transmission unit for transmitting the quantized signal output from the bandpass ΔΣ modulator;
A control unit that controls the band-pass ΔΣ modulator so that the frequency band of the modulated wave is included in a quantization noise rejection band of ΔΣ modulation performed by the band-pass ΔΣ modulator. Features transmitter.   The transmitter according to claim 1, wherein the modulation wave is a radio frequency modulation wave.   The transmitter according to claim 1, wherein the control unit further includes a function of determining a frequency of the carrier wave.   The transmitter according to any one of claims 1 to 3, wherein the frequency of the carrier wave is set within a range of a sampling frequency of the band-pass ΔΣ modulator. A volatile storage unit;
The transmitter according to any one of claims 1 to 4, wherein the storage unit is configured to be able to store frequency information indicating a frequency of the carrier wave.   The transmitter according to any one of claims 1 to 5, further comprising a function of determining the frequency of the carrier wave by frequency hopping from a plurality of predetermined frequencies. The storage unit is configured to be capable of storing pattern information related to a hopping pattern of the plurality of frequency information and frequency hopping,
The transmitter according to claim 6, wherein the control unit determines the frequency of the carrier wave by referring to the plurality of frequency information and the pattern information stored in the storage unit. A movable mobile body having a transmitter for transmitting information,
The mobile unit according to claim 1, wherein the transmission unit is the transmitter according to claim 1. A bandpass ΔΣ modulator that performs bandpass ΔΣ modulation on a modulated wave with a transmission signal added to a carrier wave;
A control unit that controls the band-pass ΔΣ modulator so that the frequency band of the modulated wave is included in a quantization noise rejection band of ΔΣ modulation performed by the band-pass ΔΣ modulator. A characteristic signal processing apparatus.