JP2008521539A - Bidirectional communication in autonomous in-vivo devices - Google Patents

Abstract

  The autonomous in-vivo detection device includes, for example, a transmitter that transmits a radio signal to an external receiver, and receives the radio signal from, for example, an external transmitter. In some embodiments, the wireless signal received by such a device includes a control signal or a command signal. A control signal or command signal causes one or more components of the device to be in an active state or an operational stop state, or to change its operational state.

Description

  The present invention relates to bidirectional communication by an in-vivo detection device, and more particularly to transmission and reception of a radio signal by the in-vivo detection device.

  Autonomous in-vivo detection devices are known. A specific autonomous in-vivo detection device has a function of starting or stopping an operation in response to various signals or stimuli. Examples of various signals or stimuli include, for example, the passage of time, changes in environmental conditions such as changes in field of view, or other factors.

  According to one embodiment of the present invention, an apparatus, system and method for an autonomous in-vivo detection device with an in-vivo transceiver are provided. The transceiver transmits, for example, a radio signal to an external receiver, and receives a radio signal from, for example, an external transmitter.

  In some embodiments, the transceiver may be a half-duplex transceiver that alternately transmits and receives. In other embodiments of the present invention, the transceiver can transmit at a higher rate than during reception. In yet another embodiment of the present invention, reception is performed by broadband communication such as spread spectrum communication. Typically, the wireless signal transmitted by the in-vivo transceiver may or may not include detection data such as image data that can be collected by the in-vivo detection device. According to embodiments of the present invention, the wireless signal received by the transceiver may be a command signal that changes one or more operating states of the in-vivo device.

The subject matter of the present invention is particularly clearly set forth in the detailed description in the specification. The invention, however, is best understood by reading the following detailed description with reference to the drawings.
For simplicity and clarity of illustration, elements in the figures are not necessarily drawn to scale or to actual dimensions. For example, for clarity, the dimensions of some elements are exaggerated relative to other elements. Alternatively, several physical components are depicted as being contained within a single functional block or element. Further, to the extent deemed appropriate, the same reference numerals have been used repeatedly in different figures to indicate corresponding or similar elements.

  In the following description, various features of the present invention will be described. For purposes of explanation, specific embodiments and details are set forth in order to provide a thorough understanding of the present invention. However, it will be apparent to those skilled in the art that the present invention may be practiced without the details described herein. Furthermore, well-known structures are omitted or simplified so as not to obscure the present invention.

  Some embodiments of the invention relate to in-vivo devices that are autonomous and typically swallowable. Other embodiments need not be swallowable. An apparatus or system according to embodiments of the present invention may be similar to the embodiments described in International Application WO 01/65995 and / or US Pat. No. 5,604,531. These are assigned to the same assignee as the present invention, the contents of which are incorporated herein by reference in their entirety. Furthermore, the reception and / or display systems that can be suitably used with embodiments of the present invention may also be similar to the embodiments described in WO 01/65995 and / or US Pat. No. 5,604,531. The devices and systems described herein may include other configurations and other sets of parts. For example, the devices and systems described herein can be used, for example, to adjust drug delivery to a target location. This is disclosed by PCT publication WO00 / 22975 (publication date: April 27, 2000). This application is assigned to the same assignee as the present application and is hereby incorporated by reference in its entirety. Other embodiments of devices, systems, and methods according to various embodiments of the present invention can also be used with other devices such as non-imaging devices and / or non-in-vivo devices.

  Please refer to FIG. FIG. 1 is a schematic diagram showing one embodiment of an in-vivo detection device, an external receiver and a transmitter system according to one embodiment of the present invention. In one embodiment, the system comprises a device (40), which is an imaging device (46), an optical system (50), a sensor (43), an illumination light source (42), a power source (45) ( For example, one or more batteries) and a controller (47). The controller (47) may be implemented as a processor or FPGA (Field Programmable Field Array), or may be implemented in a similar embodiment. Other components or sensors are also included. The controller (47) can, for example, process the signal received by the device (40) into, for example, a command or control signal. This command or control signal can cause a component that can be included in the device (40) to be in an active state, an inactive state, or to change its operational state. The device (40) may comprise a transceiver (49), which is capable of receiving wireless signals and transmitting wireless signals. The transceiver (49) may have other functions. In some embodiments, the transceiver (49) and controller (47) may be a single integrated circuit or other device, or may be included in a single integrated circuit or other device. . The device (40) may comprise an antenna (48) operably attached to the transceiver (49). In some embodiments, the antenna (48) is used for, or receives and transmits, radio signals by the transceiver (49). In other embodiments, more than one antenna may be used such as, for example, a receive antenna and / or a transmit antenna.

  Typically, the device (40) may be an autonomous swallowable capsule or may comprise such a capsule, but may have other shapes and is not swallowable. Or an autonomous device. For example, if all the parts are almost housed in a container, housing, or shell and the device (40) does not require a wired connection or a cable connection, for example to receive power or transmit information, The device (40) may be a capsule or other unit. In one embodiment, the device (40) can collect data detected from the gastrointestinal tract while passing through the gastrointestinal lumen. Other lumens may be imaged.

  A receiver (12), a transmitter (13), a controller (17), a storage device (15), and a display device (16) are arranged outside the device (40). A receiver (12) (which may be a receiver / recorder) and a transmitter (13) (typically comprising or associated with an antenna or array of antennas (antenna array)): It may be stored or provided in the same housing or unit. Alternatively, the receiver (12) and transmitter (13) may be stored in one or more separate units. For example, the transmitter (13) and receiver (12) can be stored in a portable unit that can be carried or worn by the patient and / or integrated into the transceiver.

  The receiver (12) may be connected to and / or in electrical communication with the processor (14). The processor (14) can process data signals, for example. Examples of the data signal include a signal of detected data received from the device (40) and / or control data received from the device (40). In some embodiments, the processor (14) is operatively connected to a display (16) and / or a storage system (15). Display (16) and storage system (15) display and / or store images or other detection data collected and transmitted by device (40). The processor (14) can analyze the data received by the receiver (12) and can communicate with the storage system (15). In communication with the storage system (15), the processor (14) stores image data (eg, stored or transferred as frame data) or other data in addition to transferring to the storage system (15). Transferred from the system (15). The processor (14) can also provide the analyzed data to the display (16), and the user can view the image through the display (16). The display (16) presents or displays eg image frame data or moving picture data of eg the gastrointestinal tract or other body lumen. In one embodiment, the processor (14) can perform real-time processing and / or post processing. Other monitoring and receiving systems can also be used.

  In some embodiments, the transmitter (13) and the controller (17) may be stored in the receiver. This receiver may then be worn, for example, by a patient in which the device (40) is arranged. In some embodiments, the transmitter (13) and the controller (17) may be stored elsewhere or separately. For example, by operably connecting the controller (17) to the receiver (12), an external operator who can view the detected data on the display (16) activates the transmitter (13). Thus, the transceiver (49) may be able to transmit a radio signal.

  Typically, the transmitter (13) is connected to the processor (14) and / or is in telecommunications. The processor (14) functions at least in part as a controller and / or comprises, for example, a controller (17). This controller (17) processes, for example, control commands / commands sent to the device (40) via the transmitter (13). In other embodiments of the present invention, a signal different from the control command / instruction may be processed by a processor (14) comprising a controller (17), for example, and transmitted via a transmitter (13). In yet another embodiment, the controller (17) and processor (14) may be separate units and in electrical communication with each other. In some embodiments of the present invention, for example, control commands / instructions generated by controller (17) may be based on data received by receiver (12) and processed by processor (14). Good. In some other embodiments of the present invention, the controller (17) may generate commands and / or instructions based on signals representing measurement results received at the receiver (12). In other embodiments, the control commands / instructions generated by the controller (17) may be based on data entered by the user. For example, a patient or an external operator may initiate the transmission of radio signals and / or commands from, for example, a transmitter (13) to a transceiver (49). In yet another embodiment, the control commands / instructions are based on both data entered by the user and data received and / or processed by the processor (14).

  In some embodiments, the transceiver (49) is a half-duplex transceiver, and the transceiver (49) may alternately transmit and receive, eg, via time division multiple access (TDMA). . Typically, the transmission rate to the external receiver (12) is significantly greater than the transmission rate from the external transmitter (13) to the transceiver (49). For example, the device (40) transmits image frame data to the external receiver (12) at a first rate of 1 to 10 Mbit / sec (eg, 2.7 Mbit / sec) while the transmitter (13 ) May send control commands / commands to the transceiver (49) at a rate of 10-30 Kbit / s.

  In some embodiments, in operation, device (40) may be placed, inserted, and ingested into a body lumen. This lumen includes the gastrointestinal tract or other body lumen. In some embodiments, the imager (46) captures an image of a portion of the body lumen and such image or image data is transmitted by the transceiver (49), eg, to the receiver (12). May be. At the receiver (12), the transmitted data can be viewed by an external operator or analyzed by some other function. For example, depending on the images read, analyzed, or transmitted by the device (40), an external operator can input devices (eg, keyboards, dials, etc., or other automated functions or processes, or manual functions or Using the process, a command can be sent to the controller (17) one or more times and a radio signal (eg, a control signal) can be sent from the transmitter (13) to the transceiver (49). In response to such a radio signal, the transceiver (49) and / or controller (47) commands the sensor (43), the imager (46), or any other element of the device (40). Alternatively, issue a control signal or other signal In some embodiments, signals for specific elements of the device (40) may be issued through or through the controller (47). In response to such a signal, for example, an element or sensor such as a sensor (43) or an imager (46) is brought into an active state or an operation stop state, or its operation state is changed. Actions, functions, or processes include start-up time, light intensity, release of encapsulated liquid or powder, buoyancy change, frame capture rate, image resolution, tissue sample collection, transmit power, or other Ancillary functions may be mentioned, but these are set to an active state or an operation stop state according to a signal received by the transceiver (49), or the operation state thereof is changed.

  In another embodiment of the invention, the controller (17) may analyze the parameters of the signal received at the receiver (12). Such parameters may be, for example, received power, signal quality, frequency offset, modulation index, or any other characteristic parameter of this signal. Based on this analysis, the controller (17) can send commands and / or instructions from the transmitter (13) to the transceiver (49). These commands and / or instructions are used by the controller (47) to improve the characteristics of the signal transmitted from the transceiver (49) to the receiver (12). An improvement in signal characteristics is, for example, sufficient to ensure that the signal power has sufficient signal quality at the receiver (12), correct the modulation index, correct the carrier frequency, and the like. Including ensuring that there is. Commands and / or instructions issued by the processor (14), for example using the controller (17), may be generated both automatically and manually.

  The power source (45) may comprise one or more batteries. For example, the power source (45) may comprise a silver oxide battery, a lithium battery, other suitable electrochemical cells having a high energy density, or the like. Other power sources can also be used. For example, instead of or in addition to the internal power supply (45), power may be sent to the device (40) using an external power supply.

  In some embodiments, sensor (43) may comprise a sensor relating to, for example, pH, temperature, pressure, or other physical parameters.

  Typical autonomous in-vivo device size and power limitations may limit, for example, the in-vivo receiver circuit size and / or reception capability. According to some embodiments of the present invention, spread spectrum communication is performed, for example, for high power transmission of a constant envelope signal to an in-vivo device.

  Reference is now made to FIG. 2A. FIG. 2A shows a constant envelope signal that can be used as a transmission signal for an in-vivo device according to the present invention. In some embodiments of the present invention, by using a simple amplitude modulated signal during transmission to the device (40), the circuitry required to receive and / or analyze the transmitted signal can be minimized. . The simplest form of an amplitude modulation signal is, for example, an on / off keying (OOK) modulation signal (300). The OOK modulated signal (300) includes a constant frequency carrier signal (350) typically used in short range devices (SRD). Some of the advantages of using OOK modulation include, for example, that no A / D or digital signal processing (DSP) is required, that OOK modulation is relatively insensitive to phase noise and frequency errors, and constant envelope signal Can help to deliver power efficiently.

  Typically, each symbol in OOK takes one of two values: a logical “mark” (eg “1”) or a logical “space” (eg “0”). Other encodings or semantics can also be used. For the mark (320), the transmitter (13) transmits a carrier signal (350) having a constant frequency (Fc) over the entire mark symbol. For space (330), the transmitter transmits nothing. The transceiver (49) measures the energy received during each symbol to determine whether the mark (320) or space (330) has already been transmitted. A schematic diagram of an OOK modulated signal according to the present invention in the frequency domain is shown in FIG. 2B. The transmission power of this mark or symbol is determined using known methods in the frequency domain, for example by integration of the spectral density gain over the bandwidth of the carrier signal (350). For OOK modulation, the total transmit power is limited, for example, by the normally narrow bandwidth of the signal (300).

  In vivo devices typically require higher transmit power because reception is hindered, for example, due to attenuation that occurs through body tissue. However, due to regulations such as Federal Communication Control (FCC) or other regulatory standards, the spectral density gain is, for example, less than 50.5 dBuV / m for FCC (or less for similar regulations in other countries). Limited. This requires a transmission power of about −12 dBm, but this is difficult to achieve.

  Reference is now made to FIG. 3A. FIG. 3A schematically illustrates OOK combined with a variable frequency signal. The variable frequency signal is used to transmit a command signal to the in-vivo transceiver (49) according to some embodiments of the present invention. In one embodiment of the invention, for a symbol such as mark (240), the transmitter (13) receives a variable frequency signal such as a chirp signal having a larger amplitude than the mark symbol amplitude (320), for example. Send. For symbols such as space (260), the transmitter does not transmit anything. For example, the modulation shown in FIG. 2A produces a maximum output of −23 [dBm], whereas the modulation shown in FIG. 3A gives a maximum of −9 [dBm] under the same regulatory limits. Output is achieved. By increasing the mark / symbol amplitude, for example, it is possible to compensate for attenuation occurring in living tissue. A variable frequency carrier signal is useful, for example, to distribute the spectral density over a larger range of frequencies. Thus, by combining mark amplitude or symbol amplitude with variable frequency and / or wideband frequency transmission, for example, the upper limit of FCC or other regulatory limits on communication signals can be achieved. Without exceeding, the in-vivo device can successfully receive the command signal. The transmitted carrier frequency (250) may be a variable frequency carrier in the range of 3 to 10 MHz, for example. Other suitable ranges can also be used. The corresponding frequency domain of this signal is shown schematically in FIG. 3B. Introducing a variable frequency or broadband frequency (250) increases the total transmit power while maintaining a specific (or, for example, required by regulatory standards) spectral density power (eg, the spectral density power shown in FIG. 2B). Contributes to For example, additional power can be obtained by increasing the bandwidth of the carrier signal in the frequency domain. Thus, in some embodiments of the invention, it is possible to increase the total transmit power to a desired level as long as the bandwidth is increased at the same rate. Typically, the transmitted signal has a low demand for frequency stability and phase noise. This is because such a receiver considers only the amplitude of the carrier signal and does not consider frequency components. In such a receiver, using either a single frequency or a variable frequency, the same effect is obtained as long as the total output is the same. A further advantage of such an embodiment is that a narrow band pass filter (BPF), which usually requires a lot of circuitry, is not required. Thus, according to embodiments of the present invention, command / command signals received over a wide input bandwidth are analyzed, for example, in a manner as described herein. In other embodiments of the present invention, continuous phase frequency shift keying (CPFSK) is used with, for example, two or more bits / symbols to achieve a flat spectrum and / or increase bit rate. Can be made. In other embodiments, the bit rate is increased, for example, by increasing the symbol rate. Other suitable signals can also be used to transmit command signals using spread spectrum communications.

  Reference is now made to FIG. FIG. 5 schematically illustrates a portion of a transmitter (13) that transmits an OOK signal having a wide frequency bandwidth and / or spread spectrum according to one embodiment of the present invention. In one embodiment of the present invention, elements such as an I / Q modulator (510) can be used to generate a wide bandwidth and / or spread spectrum carrier signal. This signal is amplified to a desired gain by an amplifier (520). By amplifying the signal to a desired gain, it becomes easy to receive the signal in the living body without being affected by attenuation. A switch (530) can also be used to generate a mark space modulated signal. Other methods and / or other elements (eg, scramblers) may be used to produce a signal with spread spectrum.

Reference is now made to FIGS. 4A and 4B. 4A and 4B schematically illustrate a modulated carrier frequency (400) and a constant envelope signal used as a transmission signal to an in-vivo device according to one embodiment of the present invention.
According to some embodiments of the invention, a transmitter, such as transmitter (13), transmits a variable frequency signal. An example of the variable frequency signal is a chirp signal shown in FIG. 4A. The generation of a variable frequency with a chirp pattern is called a frequency sweep. The frequency of a chirp signal or other signal varies symmetrically around a carrier frequency (Fc) (eg, 13.56 MHz ± 150 kHz). In addition, the frequency of the chirp signal increases (eg, up-chirp) (represented by reference numeral 401 in the figure) or decreases (eg, down-chirp) (represents reference numeral 402 in the figure). Each increase (401) or decrease (402) in frequency represents a logical statement in the transceiver (49) as shown in FIG. 4B. For example, FIG. 4B shows an up-chirp (403) representing a logical value “0” or space and a down-chirp (404) representing a logical value “1” or “mark” in the transceiver (49), for example. Other encodings or semantics can also be used. A chirp signal or other variable frequency carrier signal is useful, for example, to distribute the spectral density over a large range of frequencies. In addition, the data signal may be a constant envelope signal that is easy to generate. In some embodiments of the invention, the frequency sweep rate can be varied in a particular band. For example, if the frequency sweep in the down chirp signal near Fc is decelerated, it becomes possible to transmit a larger amount of power in this band.

  The modulation structure using a chirp signal may be similar to Manchester coding known in the art. Therefore, the modulation structure is invariant to changes in frequency, and communication performance is improved. Other variable frequency methods can also be used.

  Reference is now made to FIG. FIG. 6 schematically shows a block diagram of a circuit for a receiver (600) of a transceiver (49) placed in, for example, an in-vivo device (40) according to one embodiment of the present invention. . According to one embodiment of the invention, the receiver (600) may typically be a constant gain non-coherent OOK receiver. Such an OOK receiver typically receives commands / instructions in a certain format, eg, in a short range device, and in some embodiments other suitable receivers, or receivers (600). Can be used and / or other suitable signals besides the OOK modulated signal can be received. Typically, in the OOK receiver circuit (600), a band pass filter (BPF) (610) is implemented to limit noise (and / or select the expected carrier frequency (Fc) of the signal), and An envelope detector (620) can be implemented to detect marks (320) and spaces (330) in the received signal. In some embodiments of the invention, the BPF is naturally performed by the antenna (48). The antenna (48) may be an inductor in parallel with a specific capacitance that can function as a BPF. According to one embodiment, the center carrier frequency (Fc) is adjusted by controlling the capacitance in parallel with the antenna. In other embodiments, BPFs other than antennas can be used. A typical envelope detector comprises a suitable log amplifier and / or a suitable diode and RC circuit. One or more low-pass filters (LPF) (630) may be introduced for leveling effects. Also, thresholding (640) may be performed to determine whether the symbol is a mark (above threshold) or a space (below threshold). The LPF may be, for example, a typical integral and dump unit for removing noise from the envelope. Other suitable leveling methods can also be implemented. In other embodiments, the receiver (600) may be a logarithmic amplification receiver, a demodulator receiver, an IF receiver, or other suitable receiver.

  In some embodiments of the present invention, the signal rate transmitted to the transceiver (49) is on the order of about 10 to 30 Kbit / s, so typically a comparable BPF is required as a receiver. Become. However, it is not possible to implement a narrow BPF due to constraints such as space and power that exist autonomously and typically in a built-in in-vivo device. A significantly wider BPF (eg, a 3-10 MHz filter) can be used, but such a filter may be inappropriate because it receives a lot of noise and interference with the transmitted signal. In some embodiments of the invention described herein, the transmitted signal and transmitter can transmit low data rate (eg, 10-30 Kbit / s) data over a wide bandwidth (eg, spread spectrum) in vivo. Configured to be suitable for transmission to the device. However, other embodiments of the BPF may be used in other embodiments of the invention, and a narrow BPF may be incorporated into the transceiver (49).

  In a variant of the invention, each symbol consists of a narrow OOK chip or a pulsed Barker or PN sequence. Other sequences can also be used. As another sequence, for example, the sequence shown in FIG. In this sequence, for example, a mark is represented by a “0101” sequence of pulses, and a space is represented by a “1010” sequence of pulses. Other suitable sequences can be used to distinguish marks and spaces. The width of the pulse in the time domain is inversely proportional to the bandwidth in the frequency domain. In spread spectrum communications, a wide bandwidth can be obtained by implementing a narrow pulse sequence in the time domain. For example, a 10 MHz bandwidth requires 100 ns pulses each. Thus, for example, at a data rate of 20 Kbit / s, there are 500 OOK pulses in each symbol. Multiple pulses facilitate better correlation and allow the start and end of symbols to be determined more accurately. One or more symbols comprising a sequence of narrow OOK signals are shown in FIG.

  Reference is now made to FIG. FIG. 8 is a block diagram illustrating a transmitter that transmits an OOK pulse in accordance with one embodiment of the present invention. According to one embodiment of the invention, a synthesizer (810) is used to produce a constant carrier frequency. In block 20, the carrier frequency is adjusted (eg, amplified) and / or attenuated, for example, to a desired amplitude level. At block 830, a pulse is generated using an on / off switch. In other embodiments of the invention, other suitable elements may be used, or other suitable methods for generating pulses may be implemented.

  Reference is now made to FIG. FIG. 9 is a block diagram of a circuit required for receiving an OOK pulse according to an embodiment of the present invention. Such a circuit is provided, for example, in a transceiver (49). According to one embodiment of the invention, the receiver is a typical on / off keying (OOK) receiver with additional circuitry that identifies whether the symbol is a “mark” or a “space”. There may be. Typically, the OOK receiver (900) is similar to the receiver shown in FIG. 6 and is shown here with a digital add-on. In one embodiment of the present invention, this digital add-on comprises a “0” correlation block 930 and a “1” correlation block 940. A “0” correlation block 930 and a “1” correlation block 940 identify pulses and correlate sequences of pulses and / or chips. At block 950, it is determined whether the symbol is a mark symbol or a space symbol. Other suitable methods for implementing spread spectrum communications can also be used.

  In a modification of the invention, the receiver of the transceiver (49) may be a demodulation receiver. In one embodiment of the present invention, the voltage controlled oscillator (VCO) of the transmitter of the transceiver (49) can be used as a demodulator during reception. In this embodiment, the transmitter VCO is operated in a continuous wave (CW) mode without modulation. Since the same antenna is used for both transmission and reception, the VCO (105) serves, for example, as a front-end receiver for the received signal. In order to avoid attenuation due to the synthesizer loop, the frequency of the received signal needs to be outside the range of the PLL bandwidth (<10 kHz). However, it is necessary to maintain the reception signal frequency in the vicinity of the synthesizer frequency so as to obtain the amplification capability of the VCO (105). Thus, the VCO (105) can be used, for example, to amplify the received signal. In addition, the nonlinearity inherent in the VCO (105) serves as a mixer between the CW and the received signal.

  Reference is now made to FIG. FIG. 10 shows a circuit used in a demodulation receiver according to one embodiment of the present invention. Such a demodulation receiver is provided in a transceiver (49), for example. In addition to the VCO (105) and antenna (48), the circuit includes, for example, a low noise amplifier (115), a non-linear device (120), a bandpass filter (BPF) (125), a logarithmic amplifier (130), an integrator (135). ), And threshold checking methods and / or systems (140), which produce output data (145). In some embodiments of the present invention, a non-linear device (120) is required if, for example, the non-linearity of the VCO (105) is not high enough. The nonlinear device (120) is, for example, an RC and diode circuit, and this nonlinear device (120) is used for demodulation. In other embodiments, the non-linearity of the VCO (105) is sufficiently high, and the VCO (105) serves as a mixer. In this case, a low frequency product is taken from the varactor bridge of the VCO (105) (the varactor bridge receives the output of the loop filter). In this case, the nonlinear apparatus shown in FIG. 10 is not necessary. The demodulated signal is filtered using BPF (125) and then passed through logarithmic amplifier (130), as described herein. Optionally, the BPF (125) may be replaced by an LPF, for example when no DC element is present at the output of the nonlinear device (120). In other embodiments, for example, if the signal to noise ratio (SNR) (signal to noise ratio) is sufficiently high, the logarithmic amplifier (130) may be a simple RC and diode or hard limiter detector (hard). It may be replaced by a limiter detector). The advantage of the demodulating receiver is that it requires very few additional blocks in order to provide the transmitting in-vivo device with receiving capability. Another advantage is that no high gain amplifier is required and that the logarithmic amplifier operates at the IF frequency. Other elements and methods for providing a demodulating amplifier can also be implemented.

  Reference is now made to FIG. FIG. 11 shows a modified FSK modulation scheme in the frequency domain according to another embodiment of the present invention. In order to transmit the “1” symbol (325), a broadband signal located at a frequency equal to or higher than the carrier frequency is transmitted. Similarly, in order to transmit the symbol (335) of “0”, a wideband signal located at a frequency equal to or lower than the carrier frequency is transmitted. In some embodiments of the present invention, the “0” and “1” symbols are limited to the system bandwidth (301). In other embodiments of the invention, wideband signals for “0” and “1” are switched, other ranges of frequencies are used for transmission of “0” and “1”, or FSK Other suitable methods using modulation may be used.

  Several techniques can be used to create a wideband signal. According to one embodiment of the present invention, a chirp signal may be used. A chirp signal is defined as a constant envelope signal with a linear sweep of frequency, for example. The range of the frequency sweep is selected according to the bandwidth of the system (301), for example. The demodulator determines that the transmitted frequency is higher or lower than the carrier frequency or other predetermined frequency. The FSK receiver may be an FSK receiver that can be used for both normal and modified FSK modulation schemes. Other suitable FSK receivers can also be used.

  Reference is now made to FIG. FIG. 12 shows a hard limiter receiver structure according to one embodiment of the present invention. Such a receiver may be provided, for example, in a transceiver (49). The receiver may be based on standard synthesizer circuitry. In a standard synthesizer circuit, the coil of the VCO (905) serves as the antenna (906) while the VCO (905) itself is disconnected. The receiver (901) counts zero crossings in each symbol (335, 325) of the received signal. The number of zero crossings is compared to a threshold value to make a binary decision. The required gain may be a minimum gain such as a gain that enables the hard limiter (912) to operate. As an advantage of this embodiment, the counter (915) can be implemented using an existing synthesizer divider. It is possible to further simplify the scheme by dividing the output of the hard limiter (912) by a constant before counting the results. Thereby, the dynamic range of the counter (915) can be lowered. Another possibility is to use more existing units of the synthesizer. It is assumed that a frequency equal to or higher than the carrier frequency is transmitted for the “1” symbol (325), and a frequency equal to or lower than the carrier frequency is transmitted for the “0” symbol (335). Assuming that the synthesizer is operating except for the VCO (905), the voltage is raised or lowered to "0" or "1" by a charge pump on the loop filter. Therefore, the threshold (920) for the loop filter differential voltage is used for the binary decision. The comparison frequency can be increased to reduce the limit cycle phenomenon that occurs when the difference between the used frequency and the carrier frequency is too large. One advantage of this embodiment is that the structure is very simple. Most units already have a normal synthesizer structure. Another advantage is that this embodiment can use a nonlinear amplifier (909) since only zero crossing information is extracted. A low-noise amplifier (low-noise-amplifier, LNA) (907) and a non-linear amplifier (909) may perform the minimum gain and cause the hard limiter (912) to function. The constraints on the size and output of typical autonomous in-vivo devices, for example, limit the circuit size and / or receiving capability of the in-vivo receiver. According to some embodiments of the present invention, spread spectrum communication can be performed to transmit, for example, a constant envelope signal to the in-vivo device at high power.

  Reference is now made to FIG. FIG. 13 shows a portion of a transmitter for transmitting an FSK modulated signal according to one embodiment of the present invention. In one embodiment of the invention, components such as an I / Q modulator (710) may be used to generate, for example, a wideband and / or spread spectrum carrier signal. These signals are amplified or attenuated (720) to the desired gain. For example, the gain includes a gain that can be easily received in vivo without being affected by attenuation. Other methods can be used to produce an FSK modulated signal having a wideband spectrum.

  In some embodiments, the transceiver may be a single integrated circuit that both receives and transmits wireless signals. By using a single integrated circuit where the device (40) both receives and transmits wireless signals, in some embodiments, space and power requirements are relaxed. When such a single integrated circuit is not used, an autonomous in-vivo device with two-way radio capability will face these requirements.

  The transceiver (49) operates using radio waves, but in some embodiments other wireless transmission media can be used. In some embodiments, the transceiver (49) can receive a radio signal at a particular frequency and transmit a radio signal at the same frequency. In such a case or in other cases, for example, the transmission of the radio signal by the transmitter (13) is alternately performed in time with the transmission of the radio signal by the transmitter / receiver (49). Do not transmit at the same time. For example, the reception of radio signals by the transceiver (49) may be programmed to occur during any transmission waiting time. Examples of the transmission standby time include a period in which the illumination light source (42) illuminates the in vivo region. In other embodiments, radio signals can be received during other transmission waiting periods. In other embodiments of the invention, the reception period may be shorter or longer than the illumination period. In addition, the reception period may occur in an appropriate period other than the illumination period. In yet another embodiment, the transceiver (49) can transmit beacons or other transmission request signals at various intervals. Thereby, for example, it can be shown to the receiver (12) that the transmitter / receiver (49) is ready to receive the transmission.

  According to some embodiments of the present invention, the transceiver (49) can receive wireless transmissions at a frequency different from the frequency used for transmission of the transceiver (49). In such a case, for example, full-duplex communication can be performed by transmitting both the transmitter (13) and the transceiver (49) simultaneously at different frequencies.

  According to some embodiments of the present invention, a series of symbols form a packet. This packet is transmitted after each downlink channel activation and / or trigger. By executing the parsing algorithm, a packet having a parsed structure is obtained. The packet length is variable and is specified in the packet preamble.

  Some embodiments of the present invention include simple automatic repeat request (ARQ), eg, TCP / IP protocol, which provides high reliability in the communication channel. For example, a cyclic redundancy code (CRC) is provided for confirmation by the transmitter. The transceiver (49) informs the transmitter (13) whether or not the message has been transmitted correctly. If transmission fails, the message is resent until it succeeds or any timeout expires. In other embodiments of the present invention, confirmation may not be performed.

  In some embodiments, the signal transmitted from the transmitter (13) to the transceiver (49) is modulated by amplitude modulation. Alternatively or in addition, such a signal or other signal may be transmitted from or to the device (49) using frequency modulation.

  Reference is now made to FIG. FIG. 14 is a flowchart illustrating a method according to one embodiment of the present invention. At block 1410, the wireless signal is received by a transceiver within the biological device. In some embodiments, such wireless signals may or may not include control signals or command signals. In response to this control signal or command signal, such an in-vivo device is put into an active state or an operation stop state, or its operation state is changed. In some embodiments, such a radio signal may be modulated using amplitude modulation and transmitted from an external transmitter using a non-continuous high resolution signal. In some embodiments, the command or control information received by the transceiver is a small amount of information or contains a small amount of information, and a very low transmission rate (eg, in the range of 1-10 kbits) from an external receiver. May be transmitted.

  At block 1420, another wireless signal is transmitted from a transceiver in such a biological device, for example. This another radio signal may be detection data collected by such an in-vivo detection device, or may include such detection data. Examples of the detection data include image data of the gastrointestinal tract. The wireless data at block 1420 may also include a reply including a notification that the signal at block 1410 has been received. In some embodiments, the radio signal received by the transceiver may be transmitted at the same radio frequency as the radio signal transmitted by the transceiver.

  As will be apparent to those skilled in the art, the present invention is not limited by what has been particularly shown and described hereinabove. Modifications are also intended to be included within the scope of the present invention.

It is a figure which shows the in-vivo detection apparatus which concerns on one Embodiment of this invention, and a related system. It is a figure which shows the on / off keying (OOK) which can be used as a transmission signal to the in-vivo apparatus which concerns on one Embodiment of this invention. It is a figure which shows the frequency characteristic of the on / off keying (OOK) which can be used as a transmission signal to the in-vivo apparatus which concerns on one Embodiment of this invention. FIG. 6 is a diagram illustrating on / off keying modulation combined with a variable frequency signal that can be used as a transmission signal to an in-vivo device according to another embodiment of the present invention. It is a figure which shows the frequency characteristic of the on / off keying modulation combined with the signal of the variable frequency which can be used as a transmission signal to the in-vivo apparatus which concerns on another embodiment of this invention. FIG. 6 illustrates on / off keying modulation combined with a constant envelope modulated carrier signal that can be used as a transmission signal to an in-vivo device according to another embodiment of the present invention. FIG. 6 shows on / off keying modulation combined with a frequency sweep signal that can be used as a transmission signal to an in-vivo device according to another embodiment of the present invention. FIG. 3 is a diagram schematically showing a part of a transmitter for transmitting a constant envelope signal having a wide frequency band according to an embodiment of the present invention. It is a block diagram which shows roughly the circuit used for the receiving part of the transmitter / receiver which concerns on one Embodiment of this invention. FIG. 4 shows one or more symbols comprising a series of narrow OOK pulses according to one embodiment of the present invention. FIG. 2 is a block diagram illustrating a transmitter for transmitting OOK pulses according to an embodiment of the present invention. FIG. 3 is a block diagram illustrating a circuit for receiving an OOK pulse according to an embodiment of the present invention. It is a figure which shows the circuit used for the demodulation receiver which concerns on one Embodiment of this invention. FIG. 4 shows a modulated FSK scheme spectrum according to an embodiment of the present invention. It is a figure which shows the hard limiter FSK receiver which concerns on one Embodiment of this invention. It is a figure which shows a part of transmitter for transmitting the FSK modulation signal which concerns on one Embodiment of this invention. 4 is a flowchart illustrating a method according to an embodiment of the present invention.

Claims (21)

An in-vivo device, the in-vivo device comprising:
A transceiver for transmitting data to an external receiver / recorder at a first rate;
A transmitter disposed outside the in-vivo device and transmitting data at a second rate;
The in-vivo imaging system, wherein the first speed is higher than the second speed.   The system of claim 1, wherein the transmitter transmits data at the second rate using an OOK modulation structure. The transmitter transmits data using an OOK modulation structure;
The system of claim 1 wherein the OOK modulation structure causes spread spectrum by using a variable frequency signal to represent the mark.   The system of claim 1, wherein the transmitter transmits data using a variable frequency carrier signal and uses a chirp signal to cause spread spectrum.   The system of claim 1, wherein the transmitter transmits data using a variable frequency carrier signal to cause spread spectrum using a down-chirp carrier signal or an up-chirp carrier signal in a 1-bit representation. . The transceiver transmits data to the external receiver / recorder using time division multiple access;
The system of claim 1, wherein the external transmitter transmits data using a time division multiple access method.   The system of claim 1, wherein the transmitter and the receiver use different transmission frequencies.   The system of claim 1, wherein the transmitter and the transceiver transmit simultaneously, as in full duplex communication. A method for transmitting data from an in-vivo device to a receiver / recorder and transmitting data from an external transmitter to the in-vivo device, the method comprising:
Transmitting data from the in-vivo device to the receiver / recorder at a first rate;
The data includes at least image data;
The method further comprises transmitting data from the transmitter to the in-vivo device at a second rate;
The method wherein the first speed is greater than the second speed.   10. The method of claim 9, wherein the transmitter transmits data on a constant frequency carrier signal using the OOK modulation structure at the second rate. The transmitter transmits data using an OOK modulation structure;
10. The method of claim 9, wherein the OOK modulation structure forms a spread spectrum modulation structure by using a variable frequency carrier signal representing a mark.   10. The method of claim 9, wherein the transmitter uses a variable frequency carrier and transmits data using a chirp signal to form a spread spectrum modulation structure.   The method of claim 9, wherein the transmitter transmits data using a variable frequency carrier to form a spread spectrum structure using a down chirp signal or an up chirp signal in a 1-bit representation. The transceiver transmits data using time division multiple access;
The method of claim 9, wherein the transmitter transmits data using time division multiple access. An in-vivo imaging device comprising:
A transmitter / receiver for transmitting data to a receiver / recorder arranged outside the in-vivo imaging device at a first speed;
The data includes at least image data captured by an imager in the device;
The transceiver receives a command from a transmitter disposed outside the in-vivo imaging device at a second speed;
The apparatus wherein the second speed is less than the first speed.   16. The apparatus of claim 15, wherein the transmitter transmits data on a constant frequency carrier signal using the OOK modulation structure at the second rate.   16. The apparatus of claim 15, wherein the transmitter transmits data using a variable frequency carrier that represents a mark.   16. The apparatus of claim 15, wherein the transmitter transmits data using a variable frequency carrier to form a spread spectrum modulation structure using a chirp signal. An in-vivo imaging system,
The system comprises an in-vivo device;
The in-vivo device is
A transceiver for transmitting data including at least image data;
A transmitter that is arranged outside the in-vivo device and that transmits data representing a control command to the transceiver;
The data has a spread spectrum modulation structure;
The in-vivo device executes the control command.   20. The system of claim 19, wherein the transmitter causes data spread to transmit data having a variable frequency carrier.   The system of claim 19, wherein the transceiver receives data using time division multiple access.

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