Acoustic Transmission System, Primary Circuit, Secondary Circuit, Method for Transmitting and Use of an Acoustic Transmission System

Abstract

In an embodiment an acoustic transmission system includes a primary side having a transmitting unit configured to provide a transmit signal, a receiving unit configured to receive a received signal in response to the transmitted signal and an electroacoustic transducer configured to convert the transmit signal into an acoustic signal and an acoustic signal into the receive signal and a secondary side having a transponder configured to receive a receive signal and transmit a transmit signal and an electroacoustic transducer located between the primary side and the secondary side, the electroacoustic transducer having a medium permeable to acoustic signals.

Claims

1.-86. (canceled)

87. An acoustic transmission system comprising: a primary side comprising: a transmitting unit configured to provide a transmit signal; a receiving unit configured to receive a received signal in response to the transmitted signal; and an electroacoustic transducer configured to convert the transmit signal into an acoustic signal and an acoustic signal into the receive signal; and a secondary side comprising: a transponder configured to receive a receive signal and transmit a transmit signal; and an electroacoustic transducer located between the primary side and the secondary side, the electroacoustic transducer comprising a medium permeable to acoustic signals.

88. The acoustic transmission system according to claim 87, wherein the secondary side further comprises a sensor.

89. The acoustic transmission system according to claim 87, wherein the secondary side further comprises a logic circuit.

90. The acoustic transmission system according to claim 87, wherein the secondary side comprises a modulator or a MOSFET.

91. The acoustic transmission system according to claim 87, wherein the secondary side further comprises a modulator configured to modulate an electrical load on the electroacoustic transducer of the secondary side.

92. The acoustic transmission system according to claim 87, wherein the secondary side further comprises a rectifier.

93. The acoustic transmission system according to claim 92, wherein the rectifier is connected between the electroacoustic transducer and a modulator and/or is directly connected to the modulator.

94. The acoustic transmission system according to claim 87, further comprising a base of a transistor connected to a terminal (V_MOD) for load modulation.

95. The acoustic transmission system according to claim 94, wherein the transistor is a MOSFET.

96. The acoustic transmission system according to claim 94, further comprising a rectifier arranged between an electroacoustic transducer and the transistor, wherein a voltage across the electroacoustic transducer becomes non-zero when the transistor is short-circuited for load modulation.

97. The acoustic transmission system according to claim 96, wherein, during modulation, a clock is derivable on the secondary side from an incoming acoustic wave with a carrier frequency from the primary side.

98. The acoustic transmission system according to claim 87, wherein the secondary side comprises an intermediate energy storage.

99. The acoustic transmission system according to claim 87, wherein the transponder is configured to use a clock as a system clock.

100. The acoustic transmission system according to claim 87, wherein the secondary side is free of an oscillator for back communication.

101. The acoustic transmission system according to claim 87, wherein the secondary is free of an oscillator.

102. The acoustic transmission system according to claim 87, wherein the secondary side comprises an electrical impedance matching network.

103. The acoustic transmission system according to claim 87, wherein the secondary side comprises a frequency reducer.

104. The acoustic transmission system according to claim 87, wherein the secondary side comprises a circuit unit including a transformer and a parallel circuit comprising an inductive element, a capacitive element and a logic circuit.

105. The acoustic transmission system according to claim 87, wherein the secondary side comprises a logic circuit front end circuit having a port, a supply terminal, four circuit nodes, an operational amplifier and seven transistors.

106. The acoustic transmission system according to claim 87, wherein the primary side and/or the secondary side comprises an acoustic impedance matching and/or an electrical impedance matching.

107. The acoustic transmission system according to claim 87, wherein the primary side comprises a crossover.

108. The acoustic transmission system according to claim 87, wherein the primary side is configured to supply power to the secondary side.

109. The acoustic transmission system according to claim 87, wherein the acoustic transmission system is configured for unidirectional communication or bidirectional communication.

110. The acoustic transmission system according to claim 87, wherein the primary side comprises a matching network with two signal lines, a balanced guided input, an unbalanced guided output, a supply port, three inductive elements and 6 capacitive elements.

111. The acoustic transmission system according to claim 87, wherein the secondary side comprises means for recording and/or transmitting acoustic and/or optical perception.

112. The acoustic transmission system according to claim 11, wherein the secondary side comprises means for recording and/or transmitting audio recording, image recording, video recording, image-and-sound recording.

113. The acoustic transmission system according to claim 87, wherein elements of the secondary side are operable by energy transmitted from the primary side.

114. The acoustic transmission system according to claim 87, wherein information recorded on the secondary side is transmittable to the primary side in form of digital data.

115. The acoustic transmission system according to claim 87, wherein video information recorded on the secondary side is transmittable to the primary side as monochrome, grayscale or color image.

116. The acoustic transmission system according to claim 87, wherein audio information recorded on the secondary side is transmittable to the primary side as a mono or stereo signal.

117. The acoustic transmission system according to claim 87, wherein a beginning of a new image line is transmittable to an outside during the transmission of an image or moving image.

118. The acoustic transmission system according to claim 117, further comprising means for transmitting the beginning of the new image line to the secondary side.

119. The acoustic transmission system according to claim 87, wherein 3 values per pixel are transmittable during transmission of a color image from the secondary side to the primary side.

120. The acoustic transmission system according to claim 87, wherein 3 values are transmittable per pixel during transmission of a color image from the secondary side to the primary side.

121. The acoustic transmission system according to claim 87, wherein each of the primary side and the secondary side comprises a circuit with a data frame size configured for transmitting and receiving information to be transmitted.

122. The acoustic transmission system according to claim 121, wherein the data frame size is 64 bytes.

123. The acoustic transmission system according to claim 87, wherein the primary side includes a module with an antenna or the primary side is expandable by a module with an antenna.

124. The acoustic transmission system according to claim 123, wherein the module is configured for communicating with an external communication device via an air interface connection.

125. The acoustic transmission system according to claim 124, wherein the external communication device is a mobile radio terminal.

126. The acoustic transmission system according to claim 125, wherein the primary side and/or the secondary side is controllable by the external communication device.

127. The acoustic transmission system according to claim 124, wherein the air interface comprises a connection via a transceiver of a wireless standard, an NFC connection, or a Bluetooth connection.

128. The acoustic transmission system according to claim 87, wherein the primary side comprises a transducer element, an energy storage device and a circuit for converting data between different transmission standards.

129. The acoustic transmission system according to claim 128, wherein the energy storage is a battery or a rechargeable accumulator.

130. A primary circuit comprising: a transmitting unit configured to provide a transmit signal; a receiving unit configured to receive a received signal in response to the transmitted signal; and an electroacoustic transducer configured to convert the transmit signal into an acoustic signal and an acoustic signal into the receive signal.

131. A method comprising: transmitting, by a transmitting unit of a primary side, a carrier signal to a receiving unit of a secondary side; receiving, by the receiving unit, the carrier signal; generating a response signal based on a measured value; and transmitting the response signal to the primary side.

132. The method according to claim 131, wherein the primary side and the secondary side are hermetically separated and/or separated by a barrier impermeable to electromagnetic signals.

133. The method according to claim 131, wherein acoustic waves penetrate a barrier between the primary side and the secondary side and transmit information and/or energy.

134. The method according to claim 132, wherein communication is point-to-point encrypted.

135. The method according to claim 134, wherein the communication uses a cryptographic method.

136. The method according to claim 135, wherein data is encrypted so that its content is not accessible to a third party and/or is not selectively modifiable by a third party.

137. The method according to claim 131, wherein communication takes place via digital signals.

138. The method according to claim 131, wherein communication takes place unidirectionally or bidirectionally.

139. The method according to claim 131, wherein information is transmitted by modulation selected from load modulation, amplitude modulation, phase modulation, frequency modulation, or complex modulation.

140. The method according to claim 131, wherein a data flow direction includes a direction from the primary side to the secondary side.

141. The method according to claim 131, wherein modulation is any one of modulations of sections 8 and 9 of ISO/IEC14443-2_2010.

142. The method according to claim 131, wherein the method comprises error detection or error correction methods.

143. The method according to claim 131, wherein data frames are sent from the primary side to the secondary side and are responded to by the secondary side.

144. The method according to claim 143, wherein between asynchronous data frames only a non-modulated carrier frequency is sent from the primary side to the secondary side.

145. The method according to claim 131, wherein between 8 bits of user data a parity bit is sent according to ISO/IEC14443-3_2011 standard.

146. The method according to claim 131, wherein transmission comprises a Cyclic Redundancy Check (CRC) mechanism.

147. The method according to claim 146, wherein the Cyclic Redundancy Check (CRC) is a CRC16 check or CRC32 check according to ISO/IEC14443-3_2011 standard, and wherein the last 2×8 bits or 4×8 bits belong to a check, respectively.

148. The method according to claim 131, further comprising buffering energy on the secondary side.

149. The method according to claim 131, wherein longitudinal acoustic waves traverse a solid barrier.

150. The method according to claim 131, wherein communication is controlled by the primary side.

151. The method according to claim 131, wherein the primary side communicates with more than one secondary sides.

152. The method according to claim 151, wherein the method comprises an anti-collision method.

153. The method according to claim 131, wherein the method communicates at frequencies in a range of 1 MHz to 50 MHz.

154. The method according to claim 153, wherein electroacoustic communication uses frequencies in a frequency range of 13.56 MHz 0.5 MHz.

155. The method according to claim 131, wherein elements of an acoustic channel between the primary side and the secondary side are adapted to a frequency range 13.56 MHz f 0.5 MHz.

156. The method according to claim 155, wherein the elements of the acoustic channel comprise electroacoustic transducers, adhesive layers and a medium.

157. The method according to claim 131, wherein the method comprises varying frequencies and/or amplitudes to compensate for changing environmental parameters or manufacturing tolerances.

158. The method according to claim 157, wherein the varying frequencies are oriented to received digital data received by the primary side from the secondary side.

159. The method according to claim 158, wherein the secondary side first correctly receives a command from the primary side.

160. The method according to claim 159, wherein the secondary side subsequently informs the primary side about “good” or “bad” frequencies.

161. The method according to claim 160, wherein a separation into “good” and “bad” frequencies is based on a bit error rate.

162. The method according to claim 161, wherein no additional analog circuit elements are required and no evaluation of an amplitude level is necessary for classifying the frequencies into “good” and “bad” frequencies.

163. A method for using the acoustic transmission system according to claim 87, the method comprising: providing a measured value in a volume which is hermetically and/or galvanically separated from the primary side.

164. The method according to claim 163, wherein providing comprises measuring a temperature, a gas pressure, a humidity, a pH value and/or pressure in liquid media.

165. The method according to claim 164, wherein providing comprises providing a galvanically isolated transmission to an outside in a high-voltage capacitor.

166. A method according to claim 87, the method comprising: using an error detection mechanism in the acoustic transmission system according to claim 1 for finding well-suited carrier frequencies, amplitudes and/or settings of a modulation.

167. A method according to claim 87, the method comprising: using the acoustic transmission system according to claim 1 for four or more acoustic frequency ranges in which the same information is transmitted.

168. The method according to claim 167, wherein a two-stage modulation method is used in a load modulation.

169. The method according to claim 168, wherein data in Manchester coding is modulated onto a subcarrier in a first step, and wherein the subcarrier in a channel is modulated back onto a carrier frequency in a second step.

170. The method according to claim 169, wherein the primary side always receives the information of the secondary side at the same time and in parallel in four frequency bands, but which are fixed relative to s carrier.

171. The method according to claim 170, wherein information is always transmitted simultaneously in four frequency bands.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0147] Central aspects of the described devices on the primary side, on the secondary side and of the corresponding system as well as of operating methods and details of preferred embodiments are explained in more detail in the schematic figures.

[0148] FIG. 1 shows an overview of important elements of the transmission system;

[0149] FIG. 2 shows possible circuit elements on the primary side and on the secondary side;

[0150] FIG. 3 shows a more detailed view of the acoustic channel;

[0151] FIG. 4 shows a spectrum with advantageous frequencies;

[0152] FIG. 5 shows the time course of the amplitude of a signal and its response;

[0153] FIG. 6 shows a model of the acoustics of the acoustic signal;

[0154] FIG. 7 shows a possible transponder front-end circuit;

[0155] FIG. 8 shows time ranges and associated frequency ranges; and

[0156] FIGS. 9 and 10 show possibilities for contactless communication between an external circuit environment and the primary.

DETAILED DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS

[0157] FIG. 1 shows a barrier B separating a volume V on the secondary side S2 from the primary side S1. If the volume V on the secondary side S2 is hermetically separated and the barrier B is intransparent for electromagnetic and possibly magnetic signals, then usual communication paths between the primary side and the secondary side fail if a sensor for measuring a parameter is present on the secondary side and its signal is to be evaluated on the primary side S1.

[0158] However, it is possible to use the material of the barrier B as a medium M for acoustic waves to exchange information between the primary side S1 and the secondary side S2.

[0159] For this purpose, the transmission system has an electroacoustic transducer EAW on the primary side S1 and a second electroacoustic transducer EAW on the secondary side S2. Both electroacoustic transducers EAW are directly connected—e.g. by means of an adhesive—to the medium M of the barrier B. The electroacoustic transducers EAW are connected to the medium M of the barrier B by means of an adhesive. Sound waves emitted by the electroacoustic transducer EAW on the primary side S1 in the direction of the medium M can be received on the secondary side by the electroacoustic transducer EAW on the secondary side. The possibility of the electroacoustic transducers to convert between electrical signals and acoustic signals thus results in the possibility to use electrical signals on both sides of the barrier B and to use acoustic signals only for the transport of information across the barrier B. The transmission of acoustic signals also enables the simultaneous transmission of energy, so that the secondary side S2 can be supplied with energy from the primary side S1.

[0160] On the primary side S1 are a transmitting unit SE and a receiving unit EE. A transponder TP is arranged on the secondary side. The transponder TP is used for communication with the primary side S1 and serves as an interface between the electroacoustic transducer EAW on the secondary side and a logic circuit LC on the secondary side. The logic circuit LC on the secondary side can be used to control a sensor and to process the sensor signal.

[0161] FIG. 2 shows a possible form of a primary side circuit combining elements of the transmitting unit SE and the receiving unit EE. The transmitting unit SE has a first signal line SL1 and a second signal line SL2. The first signal line SL1 connects a first transmitting terminal TX1 to an electrode of the electroacoustic transducer. The second signal line SL2 connects the second transmitting terminal TX2 to the second electrode of the electroacoustic transducer. The first transmit terminal TX1 and the second transmit terminal TX2 represent the two terminals of a balanced transmit signal port of the primary side circuit. The first and second signal lines each comprise a series connection of an inductive element and a capacitive element. The inductive element is connected between the input terminal and a node A and B, respectively. The capacitive element is connected between node A or between node B and the electrode of the electroacoustic transducer. Furthermore, an inductive element connects the two electrodes of the electroacoustic transducer.

[0162] Node B is connected to ground via a capacitive element. Node A is also connected to ground via a capacitive element. Furthermore, node A is connected to an unbalanced receive terminal RX via a series connection of a resistive element and a capacitive element. A resistive element is connected between a supply terminal SUP and the receive terminal RX. The supply terminal is connected to ground via another capacitive element.

[0163] On the secondary side, the electroacoustic transducer is connected to a transformer with two magnetically coupled inductive elements. The inductive element of the transformer, which is not directly connected to the electroacoustic transducer on the secondary side, is connected to a parallel circuit consisting of an inductive element, a capacitive element and the logic circuit LC.

[0164] An input signal can be received by the transmitting unit SE from an external circuit environment through the two terminals TX1, TX2. The signal is transmitted to the primary side electroacoustic transducer via the signal conductors SL1, SL2. Corresponding acoustic waves reach the secondary-side electroacoustic transducer and are converted by it into a secondary-side electrical signal. This is transformed to suitable voltage and current values by means of the secondary-side transformer and reaches the logic circuit LC. This allows the primary side to control the activity of the secondary side. A possible response signal is transmitted by the unit of secondary side transformer and transponder TP back to the primary side S1 and can be forwarded to the external circuit environment via the output port RX.

[0165] In this case, the primary-side circuit is suitable for supplying the secondary-side circuit with energy, for example by means of a continuously transmitted, substantially sinusoidal signal of the carrier frequency, so that the provision of additional energy stores, which would otherwise have to be replaced periodically, is not necessary on the secondary side.

[0166] FIG. 3 shows the elements of the acoustic channel. Between the two EAW electroacoustic transducers is the barrier B material, which serves as a medium for propagating the acoustic waves between the transducers. Each transducer is connected to the medium M via an acoustic impedance matching element AIA. The acoustic impedance matching element AIA can be an adhesive with suitable acoustic impedance.

[0167] It is advantageous to use as thin an adhesive layer as possible or none at all.

[0168] A special impedance matching between transducer and medium is possible but not necessary.

[0169] Rather, reflections can be used to advantage in signal transmission. Thus, a “too good” matching would not be desirable here at all.

[0170] FIG. 4 shows a frequency spectrum in which the signal strength of the response is plotted as a function of frequency for various transmission conditions in the transformer on the secondary side. VK represents a critical signal strength for the strength of the received signal, above which a reliable evaluation of the received signal is possible. It has been shown that for the material combination used, operating frequencies of 9.4 MHz, 10 MHz and 10.9 MHz are suitable for both transmission ratios of 1:5 and 1:7 in the transformer.

[0171] FIG. 5 shows a possible amplitude curve for communication from the primary side to the secondary side and the corresponding response from the secondary side. The primary side uses six wave packets which are transmitted to the secondary side. After a certain waiting time (frame delay time), the secondary side responds with specific signals depending on the determined parameter value.

[0172] FIG. 6 shows an analytical model of the acoustic signal, which can be used to reproduce the signal transmission. Each of the acoustically active elements between the EAW transducers (primary side acoustic impedance matching element, barrier medium, secondary side acoustic impedance matching element) can be described by complex impedance (Z) and admittance (Y) values. Depending on the impedance jump at interfaces between different materials, an effective reflection factor results, so that the materials are easily selectable, that a high degree of signal and energy transmission to the acoustic transducer is possible.

[0173] FIG. 7 shows a possible embodiment of a transducer (i.e., transponder) front-end circuit that can be used on the secondary side between the electroacoustic transducer and the secondary-side logic circuit.

[0174] Transistors T1, T2, T3, T4, T5, T6 therein form a rectifier.

[0175] The circuit has a first input terminal A1 and a second input terminal A2 to receive the sinusoidal alternating signal of the carrier frequency of about 10 MHz, and an output terminal SUP to supply electrical power in the form of DC voltage and current to a logic circuit.

[0176] Furthermore, the circuit has four circuit nodes A, B, C, D. A capacitance between the terminals A1 and A2 represents unavoidable parasitic capacitance of the MOS transistors, as well as a capacitive element if necessary. The two transistors T3 and T4 represent switches that are controlled to be conductive or non-conductive by the voltage at their gate terminal (relative to the voltage at their source and drain terminals, respectively). Transistors T1 and T2, and transistors T6 and T7 are operated as so-called MOS diodes (gate terminal is connected to the drain terminal), i.e. their function is that of a diode. Altogether the construct results in a rectifier, which generates a DC voltage at the circuit nodes A and B, respectively also at A and D, where A represents the reference or the ground connection with 0 volts, and at B and D a voltage higher than A is formed.

[0177] To keep the DC voltage constant, a so-called voltage limiter is implemented. This consists of the operational amplifier and the transistor T5. The operational amplifier compares the DC supply voltage at point C, which is derived from the voltage at point B by a voltage divider consisting of resistors R1 and R2, with a constant voltage reference V_REF, e.g. a bandgap reference. This forms a control loop. As the AC input voltage between A1 and A2 increases, the output voltage of the op amp changes in such a way that transistor T5 becomes slightly more current conducting, i.e., its impedance between source and drain, which is at points A and D, becomes slightly lower impedance. This keeps the voltage at point B constant with respect to the reference (GND) at point A. A constant supply voltage is thus essential for the supply of the subsequent logic circuit, which has a time-variable current requirement during operation.

[0178] However, changing the impedance of transistor T5 also has an effect on the impedance applied between input terminals A1 and A2. Essentially, the voltage between A1 and A2 is also kept constant, even if the input current in A1 changes, e.g., becomes larger. This is equivalent to the input impedance between points A1 and A2 changing, depending on the regulation of transistor T5.

[0179] One can use this concept to generate load modulation. For this purpose, another transistor T8 can be used, which has its drain and source terminals in parallel with T5. The gate of T8 can now be modulated with a control voltage containing the data to be transmitted in the form of a channel coding (e.g. Manchester coding) on an auxiliary carrier frequency. The subcarrier frequency can be, for example, a frequency which is obtained by dividing the carrier frequency AC voltage between points A1 and A2, for example by dividing by factor 16 or factor 32. This subcarrier frequency can again be controlled by a data stream, e.g. in Manchester coding.

[0180] FIG. 8 shows usable signals in time and frequency domains, which result from appropriate transformations apart. Specifically, the upper part of the figure shows temporal progressions. The lower part shows associated frequency components.

[0181] In the upper part of FIG. 8, the top curve shows useful data bits for a certain time duration, specifically a zero, a one, and the transition in between. The next line shows the course of an associated channel coding. The third line shows the time history of the associated subcarrier. In the fourth line, the subcarrier modulated by means of the channel coding is shown. The last line of the upper part of FIG. 8 shows the carrier with load modulation.

[0182] The first line of the lower part of FIG. 8 represents the channel coding in the frequency domain. The second line of the lower part of FIG. 8 represents the modulated subcarrier in the frequency domain. The third line of the lower part of FIG. 8 represents the load modulation on the carrier.

[0183] I.e. via the suitably modulated subcarrier a doubling or—depending on the frequency spacing—quadrupling of transmission frequency ranges is possible. This improves interference immunity (e.g. in the case of interference by noise in the metal or interference by pronounced resonances in the metal, which statistically tend to occur only in one frequency range).

[0184] FIG. 9 shows the elements of a form of transmission system in which a module with an air interface, specifically with an NFC (near field communication) interface, is provided on the primary side. This allows the primary side to be controlled in a contactless manner via a corresponding control device, e.g., a portable communication terminal such as a cell phone with corresponding control software. For this purpose, the module on the primary side has a printed circuit board with the corresponding electronic circuit components and an antenna. The antenna can be formed directly as metallization in the printed circuit board or on the printed circuit board.

[0185] This contactless connection of the primary side can be the only connection, or in addition to a connection via another connection, such as a cable. The contactless connection can practically be used to assign the ID number of individual primary pages in a system consisting of several primary pages to a position in the system.

[0186] FIG. 10 shows a variation where the module on the primary side is controlled by another module. The additional module can be connected to an external logic circuit, e.g. a bus system of a computer. The further module then also contains the control elements for contactless communication with the primary-side module.

[0187] By means of the circuits and systems described above, it is possible easily and with little circuitry and power requirements on the secondary side to overcome barriers to communication by means of acoustic waves that are opaque to electromagnetic signals.