Clock oscillator detection

Abstract

Motion detection systems are often used to detect the presence of humans. Such motion detection systems are often based on passive infrared (PIR) sensors. Unfortunately, such detection systems cannot reliably distinguish between humans and other entities, such as animals and moving heat sources. To address this problem, in addition to detecting heat sources, it has been proposed to detect the presence of a real-time clock (RTC) device to better determine whether the detected entity is a human.

Description

[0001] Priority claim under 35 U.S.C. § 119

[0002] This application claims priority to and the benefit of U.S. Non-Provisional Application No. 16 / 203,567, filed on November 28, 2018, which is expressly incorporated herein by reference.

[0003] Public domain

[0004] One or more aspects of the present disclosure relate generally to radio wave detection, and more particularly to clock oscillator detection.

[0005] background

[0006] Motion detection systems are commonly used to detect the presence of humans. Such motion detection systems are typically based on passive infrared (PIR) sensors. Unfortunately, such detection systems cannot reliably distinguish between humans and other entities, such as animals and other moving heat sources.

[0007] Overview

[0008] This summary identifies features of some example aspects and is not an exclusive or exhaustive description of the disclosed subject matter. Whether features or aspects are included in or omitted from this summary is not intended to indicate the relative importance of these features. Additional features and aspects are described and will become apparent to those skilled in the art upon reading the following detailed description and viewing the accompanying drawings that form a part of this detailed description.

[0009] An exemplary oscillator detector is disclosed. The oscillator detector may include an antenna, a bandpass filter, a signal processor, and a control circuit. The antenna may be configured to receive a radio signal, which may include real-time clock (RTC) radiation. The RTC radiation may be a radio wave emitted by an RTC device at an RTC frequency. The bandpass filter may be configured to filter the radio signal received by the antenna and output a filtered radio signal. The bandpass filter may be tuned to the RTC frequency. The signal processor may be configured to process the filtered radio signal and output radio signal data. The control circuit may be configured to detect the RTC device based on the radio signal data.

[0010] An exemplary detection system is disclosed. The detection system may include a motion detector, an oscillator detector, and a controller. The motion detector may be configured to detect an entity. The oscillator detector may be configured to detect a real-time clock (RTC) device operating at an RTC frequency. The controller may be configured to determine whether the entity is a human based on whether the motion detector detects the entity and whether the oscillator detector detects the RTC device.

[0011] An exemplary method is disclosed. The method may include detecting an entity using a motion detector of a detection system. The method may also include detecting a real-time clock (RTC) device operating at an RTC frequency using an oscillator detector of the detection system. The method may also include determining whether the entity is a human based on whether the entity is detected and whether the RTC device is detected using a controller of the detection system.

[0012] Another exemplary oscillator detector is disclosed. The oscillator detector may include a device for receiving a radio signal, a device for bandpass filtering, a device for signal processing, and a device for detecting. The device for receiving a radio signal may receive a radio signal, which may include real-time clock (RTC) radiation. The RTC radiation may be a radio wave emitted by an RTC device at an RTC frequency. The device for bandpass filtering may filter the radio signal received by the device for receiving a radio signal. The device for bandpass filtering may also output a filtered radio signal. The device for bandpass filtering may be tuned to the RTC frequency. The device for signal processing may process the filtered radio signal and output radio signal data. The device for detecting may detect the RTC device based on the radio signal data. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] The accompanying drawings are presented to aid in describing examples of one or more aspects of the disclosed subject matter and are provided solely for the purpose of illustrating the examples and not limiting thereof:

[0015] Figure 1 explaining an example scenario in which a detection system is used to detect whether an entity is a human;

[0016] Figure 2 An example scenario in which an oscillator detector is used to detect a real-time clock device is explained;

[0017] Figure 3 A flow chart illustrating an example method performed by a detection system;

[0018] Figure 4 a flow chart illustrating an example process performed by an oscillator detector for detecting a real time clock device; and

[0019] Figure 5 An example of an apparatus in which the device is integrated is illustrated.

[0020] Detailed Description

[0021] Various aspects of the subject matter are provided in the following description and related drawings of specific examples of the disclosed subject matter. Alternative solutions can be designed without departing from the scope of the disclosed subject matter. In addition, well-known elements will not be described in detail or will be omitted to avoid confusing relevant details.

[0022] The word "exemplary" is used herein to mean "serving as an example, instance, or illustration." Any embodiment described herein as "exemplary" is not necessarily to be construed as preferred or advantageous over other embodiments. Likewise, the term "embodiment" does not require that all embodiments of the disclosed subject matter include the discussed feature, advantage, or mode of operation.

[0023] The terms used herein are for the purpose of describing specific examples only and are not intended to be limiting. As used herein, the singular forms of "a", "a", and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will also be understood that the terms "include", "have", "include" and / or "contain" when used herein indicate the presence of stated features, integers, processes, operations, elements, and / or components, but do not exclude the presence or addition of one or more other features, integers, processes, operations, elements, components and / or groups thereof.

[0024] In addition, many examples are described in the form of sequences of actions to be performed by, for example, elements of a computing device. It will be appreciated that the various actions described herein can be performed by a dedicated circuit (e.g., an application specific integrated circuit (ASIC)), by program instructions being executed by one or more processors, or by a combination of the two. In addition, the sequences of actions described herein may be considered to be fully embodied in any form of computer-readable storage medium, which has stored therein a corresponding set of computer instructions that, upon execution, will cause an associated processor to perform the functionality described herein. Thus, various aspects may be embodied in a number of different forms, all of which have been contemplated to fall within the scope of the claimed subject matter. In addition, for each example described herein, the corresponding form of any such example may be described herein as, for example, "logic configured to perform the described actions."

[0025] Recall from above that typical motion detection systems designed to detect human presence, such as those based on passive infrared (PIR) devices, cannot reliably distinguish between humans and other heat-generating objects, such as animals and other moving heat sources (e.g., vents releasing hot air).

[0026] One aspect that typically distinguishes humans from animals and other heat-generating objects is that humans tend to be equipped with electronic devices, such as digital watches and smart phones. Therefore, in order to solve one or more problems associated with conventional detection systems, it is proposed to detect the presence of electronic devices. In particular, it is proposed to detect the presence of a clock oscillator in a real-time clock (RTC) device. Many electronic devices contain at least one oscillator that is used as a timing source for the RTC or for other purposes. There are many portable devices that contain RTCs. Such portable devices are typically body-worn or otherwise carried with you.

[0027] Convention is to use 32,768Hz (2 15 Hz) oscillator. This frequency can be divided by 2 to the 15th power to give one tick per second. Division by any power of 2 is easy to implement in digital gates and has therefore become popular. Due to the convenience of dividing by the number 32,768 in cheap digital circuitry, accurate oscillators running at 32,768 Hz have become ubiquitous. The end result is that there are billions of electronic devices using the same 32,768 Hz RTC frequency.

[0028] Economies of scale have made the quartz crystals used as the basis for such oscillators extremely cheap, effectively establishing 32,768Hz as the de facto frequency standard. All electronic oscillators generate electromagnetic radiation to some extent, whether intentional or unintentional. RTC devices with 32,768Hz oscillators are rarely shielded to prevent electromagnetic radiation. This is because the 32,768Hz frequency is significantly separated from frequencies commonly used for radio communications.

[0029] In one aspect, a sensitive oscillator detector, which may be a radio frequency detector tuned to the RTC frequency (e.g., 32,768 Hz), may be used to detect the proximity of an electronic device containing such an oscillator. Since more and more electronic devices are body-worn or carried on the body, detecting nearby radio signals at the RTC frequency may be used to detect human proximity to the oscillator detector.

[0030] In one aspect, the oscillator detector can be as Figure 1 The explained combination with motion detector, Figure 1 A scenario 100 is illustrated in which a detection system 130 can be used to detect whether a human is proximate to the detection system 130. In this example, an entity 110 (e.g., a human) is illustrated as having a portable device 120 incorporating an RTC device 125. The portable device 120 may be a body-worn device. Although not illustrated, there may of course be multiple portable devices 120 incorporating an RTC device 125.

[0031] The detection system 130 may include a motion detector 133, an oscillator detector 135, and a controller 137. An example of the motion detector 133 may be an infrared (IR) based sensor, such as a PIR sensor. The motion detector 133 may be configured to detect an entity 110 that is adjacent to the detection system 130. For example, the motion detector 133 may detect the entity 110 when the entity 110 is within a detection range of the motion detector 133. Alternatively or additionally, the motion detector 133 may be configured to provide motion data to the controller 137, which may determine from the motion data whether the entity 110 has been detected.

[0032] The oscillator detector 135 may be configured to detect the RTC device 125 when the RTC device 125 is proximate to the detection system 130. For example, the oscillator detector 135 may detect the RTC device 125 when the RTC device 125 is within a detection range of the oscillator detector 135. Alternatively or additionally, the oscillator detector 135 may be configured to provide oscillator data to the controller 137, which may determine from the oscillator data whether the RTC device 125 has been detected.

[0033] In one aspect, the oscillator detector 135 can detect the presence or absence of RTC radiation. In this context, RTC radiation can be considered as radio waves emitted by the RTC device 125 at the RTC frequency. The RTC frequency can be 2 N Hz, where N is a non-negative integer, ie, N ≥ 0. When N = 15, the RTC frequency is 32,768 Hz. The details of the oscillator detector 135 will be further presented below.

[0034] The controller 137 may be a decision element that evaluates signals from both the motion detector 133 and the oscillator detector 135 to determine whether a human is nearby. For example, the controller 137 may be configured to determine whether the entity 110 is a human based on whether the entity 110 has been detected (by the motion detector 133 itself or by the controller 137 from the motion data provided by the motion detector 133) and whether the RTC device 125 has been detected (by the oscillator detector 135 itself or by the controller 137 from the oscillator data provided by the oscillator detector 135). For example, when both the entity 110 and the RTC device 125 have been detected, the controller 137 may determine that the entity 110 is a human.

[0035] about Figure 1The illustrated detection system 130 will assume the following in the following discussion. First, it will be assumed that the motion detector 133 is configured to detect the entity 110. Second, it will be assumed that the oscillator detector 135 is configured to detect the RTC device 125. However, it is relatively straightforward to conceive of an alternative detection system in which the controller 137 processes one or both of the motion data and the oscillator data to make a similar determination. Therefore, a detailed description of such an alternative detection system 130 will be omitted.

[0036] Reference Figure 1 As illustrated in the detection system 130, the controller 137 may determine that the entity 110 is a human being when it is determined that the entity 110 and the RTC device 125 are proximate to the detection system 130. That is, when the motion detector 133 detects the entity 110 and when the oscillator detector 135 detects the RTC device 125, the controller 137 may determine that the entity 110 is a human being. By considering the detection results from both the motion detector 133 and the oscillator detector 135, greater reliability may be achieved than by relying on either type of detection for a single type.

[0037] If the detection results of the motion detector 133 and the oscillator detector 135 verify each other, reliability can be enhanced. For example, the motion detector 133 can be configured to determine the distance of the entity 110 (for convenience, referred to as "entity distance"), and the oscillator detector 135 can be configured to determine the distance of the RTC device 125 (for convenience, referred to as "RTC device distance"). The entity and RTC device distance can be the distance from the detection system 130. The controller 137 can be configured to determine that the entity 110 is a human being when the entity distance and the RTC device distance are within a threshold distance difference from each other. The threshold distance difference can be predetermined. Alternatively, the threshold distance difference can be configured during operation. The threshold distance difference can be set to be within the measurement error margin of the distance of the motion detector 133 and the oscillator detector 135.

[0038] As another example, the motion detector 133 may be configured to determine the direction of the entity 110 (referred to as the "entity direction" for convenience), and the oscillator detector 135 may be configured to determine the direction of the RTC device 125 (referred to as the "RTC device direction" for convenience). The entity and RTC device directions may be directions relative to the detection system 130. The controller 137 may be configured to determine that the entity 110 is a human when the entity direction and the RTC device direction are within a threshold direction difference of each other. The threshold direction difference may be predetermined. Alternatively, the threshold direction difference may be configured during operation. The threshold direction difference may be set to be within a measurement error margin of the directions of the motion detector 133 and the oscillator detector 135.

[0039] As a further example, both direction and distance can be combined. That is, the motion detector 133 can be configured to determine the position (e.g., a combination of direction and distance) of the entity 110 (for convenience referred to as "entity position"), and the oscillator detector 135 can be configured to determine the position of the RTC device 125 (for convenience referred to as "RTC device position"). The entity and RTC device positions can be positions relative to the detection system 130. The controller 137 can be configured to determine that the entity 110 is a human being when the entity position and the RTC device position are within a threshold position difference of each other. The threshold position difference can be predetermined. Alternatively, the threshold position difference can be configured during operation. The threshold position difference can be set to be within the measurement error margin of the distance and direction of the motion detector 133 and the oscillator detector 135.

[0040] The controller 137 may advantageously use the direction detection capabilities of the motion detector 133 and / or the oscillator detector 135. For example, when the oscillator detector 135 detects the RTC device direction, the controller 137 may be configured to orient the motion detector 133 toward the RTC device direction. Alternatively or additionally, when the motion detector 133 detects the entity direction, the controller 137 may be configured to orient the oscillator detector 135 toward the entity direction.

[0041] Figure 2 An example scenario in which an oscillator detector 135 can be used to detect an RTC device 125 is illustrated. As noted above, the RTC device 125 can be incorporated into the portable device 120. The RTC device 125 is illustrated as emitting RTC radiation 205, which is a radio wave generated from the operation of the RTC device 125. Typically, the RTC radiation 205 is unintended radiation. They are generated as a byproduct of the operation of the RTC device 125. However, since the radio signal at the RTC frequency (e.g., 32,768 Hz) is greatly different from the frequency typically used for wireless communication, the RTC radiation 205 does not typically interfere with wireless communication. Therefore, special measures are not typically taken to shield the RTC radiation 205.

[0042] The oscillator detector 135 may include an antenna 210, a bandpass filter 220, an amplifier 230, a signal processor 240, and a control circuit 250. The antenna 210 may be configured to receive a radio signal including RTC radiation 205 from the RTC device 125. As noted above, the RTC radiation 205 may be described as being emitted by the RTC device 125 at an RTC frequency (e.g., 2 15Hz). Although the singular form "antenna" is used, it should be noted that antenna 210 can be implemented in various forms. Antenna 210 can include any number of (one or more) physical antennas. Antenna 210 can also be directional so that the starting direction of RTC radiation 205 can be determined.

[0043] The bandpass filter 220 may be configured to bandpass filter the radio signal received by the antenna 210 and output the filtered radio signal. The bandpass filter 220 may be tuned to the RTC frequency (eg, 2 N Hz, N≥0). In one embodiment, the bandpass filter 220 can be a narrow bandwidth crystal ladder filter, which includes multiple RTC frequency crystals (e.g., with a nominal resonant frequency of 32,768 Hz) that vibrate at the RTC frequency. In other words, multiple crystals can be arranged in a filter topology that exhibits a peak response at the RTC frequency. Due to the widespread nature of RTC devices, very accurate crystals of this frequency are widely available and inexpensive. As a result, the bandwidth of the bandpass filter 220 can be made very narrow. For example, a bandwidth as narrow as 2.0 Hz or less can be achieved using a typical ladder filter including four appropriately matched crystals. This means that the bandpass filter 220 can be fine-tuned to detect the RTC frequency with a very high Q factor. For example, a Q factor of 16,000 or more can be achieved using a typical ladder filter.

[0044] On the one hand, signal processor 240 can process the filtered radio signal from bandpass filter 220 and output radio signal data.But on the other hand, amplifier 230 can be configured to amplify the filtered radio signal from bandpass filter 220.Signal processor 240 can then process the amplified filtered radio signal from amplifier 230 to output radio signal data.As mentioned above, the RTC radiation 205 from RTC device 125 is not shielded or shielded and is not emitted.Nevertheless, these unexpected transmissions can be weak transmissions.Therefore, amplifier 230 can improve the sensitivity of oscillator detector 135 as a whole.

[0045] The control circuit 250 can be configured to communicate with a device external to the oscillator detector 135 (eg, with the controller 137). In one aspect, the control circuit 250 can forward the radio signal data to the controller 137 as oscillator data.

[0046] In another aspect, however, control circuit 250 may be configured to detect RTC device 125 based on radio signal data from signal processor 240. For example, control circuit 250 may determine that RTC device 125 has been detected when the radio signal data indicates that the intensity level of RTC radiation 205 is above the RTC threshold level.

[0047] The RTC threshold level can be set, for example, by the control circuit 250 and / or the controller 137 in consideration of the environmental level of the source of the electrical noise and RTC radiation 205 in the operating environment of the oscillator detector 135. For example, one or more RTC devices 125 (not shown) may be present in the detection system 130. In other words, one or more "internal" RTC devices 125 may be present. Similarly, the operating environment of the detection system 130 may include a device (not shown) that incorporates the RTC device. The RTC threshold level may be set to account for these "expected" RTC radiations 205. Subsequently, the RTC device 125 to be detected will cause the RTC radiation 205 to increase above the RTC threshold level that has accounted for the expected RTC radiation 205. In one embodiment, some or all of the internal RTC devices 125 may be shielded or otherwise shielded. In this instance, the RTC threshold level may be reduced accordingly.

[0048] The RTC radiation level can be used to determine the distance of the RTC device 125. Specifically, the control circuit 250 can be configured to determine the distance between the RTC device 125 and the oscillator detector 135 (or between the RTC device 125 and the detection system 130) based on the radio signal data. Likewise, changes in the RTC radiation level can be used to detect the direction of motion, e.g., movement toward / away from the oscillator detector 135 / detection system 130.

[0049] In some environments, the intensity of the RTC radiation 205 level can be used to enable an action. For example, if a human presents a portable device 120 (e.g., a quartz watch, a cell phone, etc.) incorporating an RTC device 125 to the detection system 130, the control circuit 250 or the controller 137 can enable an action (such as starting a machine, operating a door, etc.). When the RTC device 125 is purposefully presented, the intensity of the RTC radiation 205 should be quite strong. Therefore, in one aspect, when the intensity level of the RTC radiation 205 is above the action threshold level, the control circuit 250 or the controller 137 can initiate an action. The action threshold level should be significantly higher than the RTC threshold level, for example, 10 dB or more higher.

[0050] When the antenna 210 is a directional antenna, the control circuit 250 can determine the lateral (left / right) and vertical (up / down) directions of the RTC device 125 in addition to determining the distance. That is, the control circuit 250 can be configured to detect the position of the RTC device 125. A logical extension is that the control circuit 250 can also be configured to determine the movement of the RTC device 125 in all directions. Such capabilities may be very useful in emergency situations, such as detecting a person buried by an avalanche.

[0051] Figure 3A flow chart illustrating an example method 300 performed by a detection system, such as the detection system 130. At 310, the motion detector 133 may detect the entity 110 when the entity 110 is proximate to the detection system 130. At 320, the oscillator detector 135 may detect the RTC device 125 when the RTC device 125 is proximate to the detection system 130.

[0052] Figure 4 Flowchart illustrating an example process performed by the oscillator detector 135 to implement 320. At 410, the antenna 210 may receive a radio signal including the RTC radiation 205 from the RTC device 125. At 420, the bandpass filter 220 may bandpass filter the radio signal received by the antenna 210 and output the filtered radio signal. At 430, the amplifier 230 may amplify the filtered radio signal from the bandpass filter 220. At 440, the signal processor 240 may process the filtered radio signal (whether amplified or not) and output the radio signal data. At 450, the control circuit 250 may detect the RTC device 125 based on the radio signal data.

[0053] Reference Figure 3 At 330, the controller 137 may determine whether the entity 110 is a human based on whether the entity 110 is detected and whether the RTC device 125 is detected. For example, at 330, when the entity 110 is detected and when the RTC device 125 is detected, it may be determined that the entity 110 is a human.

[0054] Recall that in one aspect, when entity 110 is detected, motion detector 133 can determine the entity distance, and when RTC device 125 is detected, oscillator detector 135 can determine the RTC device distance. Then at 330, when the entity distance and the RTC device distance are within a threshold distance difference of each other, it can be determined that entity 110 is a human.

[0055] Recall that in another aspect, when entity 110 is detected, motion detector 133 can determine the entity direction, and when RTC device 125 is detected, oscillator detector 135 can determine the RTC device direction. Then at 330, when the entity direction and the RTC device direction are within a threshold direction difference of each other, it can be determined that entity 110 is a human.

[0056] Of course, distance and direction can be combined. That is, in yet another aspect, when entity 110 is detected, motion detector 133 can determine the entity position, and when RTC device 125 is detected, oscillator detector 135 can determine the RTC device position. Then at 330, when the entity position and the RTC device position are within a threshold direction difference of each other, it can be determined that entity 110 is a human.

[0057] It should be noted that it is not Figure 3 and 4 All the illustrated blocks need to be executed, that is, some blocks may be optional. Moreover, the numerical references to the blocks in these figures should not be considered as requiring that these blocks should be executed in a particular order. In fact, some blocks may be executed concurrently.

[0058] Figure 5 Explains the Figure 2 The aforementioned oscillator detector 135 or Figure 1 Various electronic devices integrated with the illustrated detection system 130. For example, mobile phone device 502, laptop device 504, terminal device 506, and security devices incorporating oscillator detector 135 / detection system 130 as described herein may include apparatus 500. Apparatus 500 may be a stand-alone device such as a sensor, a fixed sensor, an IoT (Internet of Things) device, etc. Figure 5 The devices 502, 504, 506 illustrated in the figure are merely exemplary. Other electronic devices can also feature the apparatus 500, including, but not limited to, a group of devices (e.g., electronic devices) including: security devices, mobile devices, handheld personal communication system (PCS) units, portable data units (such as personal digital assistants), devices enabled with a global positioning system (GPS), navigation devices, set-top boxes, music players, video players, entertainment units, fixed location data units (such as meter reading equipment), communication devices, smart phones, tablet computers, computers, wearable devices, servers, routers, electronic devices implemented in motor vehicles (e.g., autonomous vehicles), or any combination thereof.

[0059] Those skilled in the art will appreciate that information and signals may be represented using any of a variety of different technologies and techniques. For example, data, instructions, commands, information, signals, bits, symbols, and chips that may be referred to throughout the above description may be represented by voltage, current, electromagnetic waves, magnetic fields or magnetic particles, optical fields or optical particles, or any combination thereof.

[0060] In addition, those skilled in the art will appreciate that the various illustrative logic blocks, modules, circuits, and algorithms described in conjunction with the examples disclosed herein can be implemented as electronic hardware, computer software, or a combination of the two. To clearly illustrate this interchangeability of hardware and software, various illustrative components, blocks, modules, circuits, and methods are generally described above in terms of their functionality. Whether such functionality is implemented as hardware or software depends on the specific application and the design constraints imposed on the overall system. The technician can implement the described functionality in different ways for each specific application, but such implementation decisions should not be interpreted as causing a departure from the scope of the present disclosure.

[0061] The methods, sequences and / or algorithms described in conjunction with the examples disclosed herein may be embodied directly in hardware, in a software module executed by a processor, or in a combination of the two. The software module may reside in a RAM memory, a flash memory, a ROM memory, an EPROM memory, an EEPROM memory, a register, a hard disk, a removable disk, a CD-ROM, or any other form of storage medium known in the art. An exemplary storage medium is coupled to a processor so that the processor can read and write information from / to the storage medium. In an alternative, the storage medium may be integrated into the processor.

[0062] Thus, one aspect may include a computer readable medium implementing any of the above-described apparatuses.Thus, the scope of the disclosed subject matter is not limited to the illustrated examples and any means for performing the functionality described herein is included.

[0063] Although the above disclosure shows illustrative examples, it should be noted that various changes and modifications may be made therein without departing from the scope of the disclosed subject matter as defined by the appended claims. The functions, processes, and / or actions of the method claims according to the examples described herein do not have to be performed in any particular order. Furthermore, although elements of the disclosed subject matter may be described or claimed in the singular, the plural is also contemplated unless limitation to the singular is explicitly stated.

Claims

1. An oscillator detector, comprising: an antenna configured to receive a radio signal, the radio signal comprising a real time clock (RTC) radiation, the RTC radiation being a radio wave emitted by an RTC device at an RTC frequency; a bandpass filter configured to bandpass filter the radio signal received by the antenna and output a filtered radio signal, the bandpass filter being tuned to the RTC frequency; a signal processor configured to process the filtered radio signal and output radio signal data; as well as a control circuit configured to detect the RTC device based on the radio signal data, Wherein the control circuit is configured to determine that the RTC device has been detected when the intensity level of the RTC radiation is above an RTC threshold level, the RTC threshold level being set taking into account RTC radiation from one or more internal RTC devices incorporated into a detection system of the oscillator detector.

2. The oscillator detector of claim 1, wherein the RTC frequency is 2 N A fixed frequency in Hz, where N is a non-negative integer.

3. An oscillator detector as claimed in claim 2, wherein N=15.

4. The oscillator detector of claim 1, wherein the bandpass filter is a crystal ladder filter comprising a plurality of crystals arranged in a filter topology that exhibits a peak response at the RTC frequency.

5. The oscillator detector of claim 1 , further comprising: an amplifier configured to amplify the filtered radio signal, Wherein the signal processor is configured to process the amplified filtered radio signal to output the radio signal data.

6. The oscillator detector of claim 1, wherein the control circuit is configured to determine a distance of the RTC device from the oscillator detector based on the radio signal data.

7. The oscillator detector according to claim 1, wherein the antenna is a directional antenna, and wherein the control circuit is configured to determine based on the radio signal data: the distance between the RTC device and the oscillator detector, or the orientation of the RTC device relative to the oscillator detector, or Both of these.

8. The oscillator detector of claim 1, wherein the RTC device is incorporated into a portable device.

9. The oscillator detector of claim 8, wherein the portable device is a body-worn device.

10. The oscillator detector of claim 1, wherein the oscillator detector is incorporated into a device selected from the group consisting of a security device, a mobile device, a handheld personal communication system (PCS) unit, a portable data unit, a global positioning system (GPS) enabled device, a navigation device, a set-top box, a music player, a video player, an entertainment unit, a fixed location data unit, a communication device, a smart phone, a tablet computer, a computer, a wearable device, a server, a router, an electronic device implemented in a motor vehicle, or any combination thereof.

11. The oscillator detector of claim 1 , wherein the oscillator detector is incorporated into a detection system configured to detect an entity using an entity detector and to determine whether the entity is a human based on whether the oscillator detector detects the RTC device.

12. The oscillator detector of claim 1, wherein the bandwidth of the bandpass filter is 2 Hz or less.

13. The oscillator detector of claim 1, wherein a Q factor of the bandpass filter is 16,000 or higher.

14. A method of an oscillator detector, the method comprising: receiving via an antenna a radio signal, the radio signal comprising real time clock (RTC) radiation, the RTC radiation being radio waves emitted by an RTC device at an RTC frequency; filtering the radio signal received by the antenna using a bandpass filter tuned to the RTC frequency to output a filtered radio signal; processing the filtered radio signal using a signal processor to output radio signal data; as well as Based on the radio signal data, using a control circuit to detect the RTC device, Wherein the control circuit is configured to determine that the RTC device has been detected when the intensity level of the RTC radiation is above an RTC threshold level, the RTC threshold level being set taking into account RTC radiation from one or more internal RTC devices incorporated into a detection system of the oscillator detector.

15. The method of claim 14, wherein the RTC frequency is 2 N A fixed frequency in Hz, where N is a non-negative integer.

16. The method of claim 14, further comprising: amplifying the filtered radio signal using an amplifier to output a filtered radio signal, Wherein processing the filtered radio signal comprises processing the amplified filtered radio signal using the signal processor to output the radio signal data.

17. The method of claim 14, further comprising: Based on the radio signal data, the control circuit is used to determine a distance of the RTC device from the oscillator detector.

18. The method of claim 14, wherein the antenna is a directional antenna, and Wherein the method further comprises: The control circuit is used to determine a distance between the RTC device and the oscillator detector based on the radio signal data, and / or the control circuit is used to determine an orientation of the RTC device relative to the oscillator detector based on the radio signal data.

19. An oscillator detector comprising: means for receiving a radio signal, the radio signal comprising a real time clock (RTC) radiation, the RTC radiation being a radio wave emitted by an RTC device at an RTC frequency; means for bandpass filtering the radio signal received by the means for receiving the radio signal, the means for bandpass filtering outputting a filtered radio signal, the means for bandpass filtering being tuned to the RTC frequency; means for signal processing said filtered wireless telecommunication, the means for signal processing outputting wireless signal data; as well as means for detecting said RTC device based on said radio signal data, Wherein the means for detecting determines that the RTC device has been detected when the intensity level of the RTC radiation is above an RTC threshold level, wherein the RTC threshold level is set taking into account RTC radiation from one or more internal RTC devices incorporated into a detection system of the oscillator detector.

20. The oscillator detector of claim 19, wherein the oscillator detector is incorporated into a detection system configured to detect an entity using a means for detecting, and to determine whether the entity is a human based on whether the oscillator detector detects the RTC device.

21. A detection system comprising: a motion detector configured to detect an entity; an oscillator detector configured to detect a real time clock (RTC) device operating at an RTC frequency by detecting the presence of RTC radiation; as well as a controller configured to determine whether the entity is a human based on whether the motion detector detects the entity and whether the oscillator detector detects the RTC device, Wherein the controller is configured to determine that the RTC device has been detected when an intensity level of the RTC radiation is above an RTC threshold level, the RTC threshold level being set taking into account RTC radiation from one or more internal RTC devices incorporated into a detection system of the oscillator detector.

22. The detection system of claim 21, wherein the oscillator detector comprises: an antenna configured to receive a radio signal, the radio signal comprising RTC radiation, the RTC radiation being radio waves emitted by the RTC device at the RTC frequency; a bandpass filter configured to bandpass filter the radio signal received by the antenna and output a filtered radio signal, the bandpass filter being tuned to the RTC frequency; a signal processor configured to process the filtered radio signal and output radio signal data; as well as A control circuit is configured to detect the RTC device based on the radio signal data.

23. The detection system as claimed in claim 22, wherein the RTC frequency is 2 N A fixed frequency in Hz, where N is a non-negative integer.

24. The detection system of claim 22, wherein the bandpass filter is a crystal ladder filter comprising a plurality of crystals arranged in a filter topology that exhibits a peak response at the RTC frequency.

25. The detection system of claim 21, wherein the motion detector is an infrared (IR) based detector.

26. The detection system according to claim 21, wherein the motion detector is configured to detect a direction of the entity and the controller is configured to orient the oscillator detector towards the direction of the entity, or wherein the oscillator detector is configured to detect the direction of the RTC device, and the controller is configured to orient the motion detector towards the direction of the RTC device, or Both of these.

27. The detection system of claim 21, wherein the controller is configured to determine that the entity is a human when the motion detector detects the entity and when the oscillator detector detects the RTC device.

28. The detection system according to claim 21, wherein the motion detector is configured to determine an entity distance, the entity distance being the distance of the entity from the detection system, wherein the oscillator detector is configured to determine an RTC device distance, the RTC device distance being the distance of the RTC device from the detection system, and Wherein the controller is configured to determine that the entity is a human being when the entity distance and the RTC device distance are within a threshold distance difference of each other.

29. The detection system according to claim 21, wherein the motion detector is configured to determine an entity direction, the entity direction being the direction of the entity relative to the detection system, wherein the oscillator detector is configured to determine an RTC device orientation, the RTC device orientation being an orientation of the RTC device relative to the detection system, and Wherein the controller is configured to determine that the entity is a human when the entity direction and the RTC device direction are within a threshold direction difference of each other.

30. The detection system of claim 21, wherein the RTC device is incorporated into a portable device.

31. A method comprising: Detecting entities using a motion detector of a detection system; Using an oscillator detector of the detection system to detect a real-time clock (RTC) device operating at an RTC frequency by detecting the presence of RTC radiation; using a controller of the detection system to determine whether the entity is a human based on whether the entity is detected and whether the RTC device is detected, Wherein the controller is configured to determine that the RTC device has been detected when an intensity level of the RTC radiation is above an RTC threshold level, the RTC threshold level being set taking into account RTC radiation from one or more internal RTC devices incorporated into a detection system of the oscillator detector.

32. The method of claim 31, wherein the oscillator detector comprises an antenna, a bandpass filter, a signal processor and a control circuit, and Wherein detecting the RTC device comprises: receiving, using the antenna, a radio signal comprising RTC radiation, the RTC radiation being radio waves emitted by the RTC device at the RTC frequency; using the bandpass filter tuned to the RTC frequency, bandpass filtering the radio signal received by the antenna and outputting a filtered radio signal; processing the filtered radio signal using the signal processor and outputting radio signal data; as well as The RTC device is detected based on the radio signal data using the control circuit.

33. The method of claim 32, wherein the RTC frequency is 2 N A fixed frequency in Hz, where N is a non-negative integer.

34. The method of claim 31, wherein the entity is determined to be a human when the entity is detected and when the RTC device is detected.

35. The method of claim 31, wherein an entity distance is determined when the entity is detected, the entity distance being the distance between the entity and the detection system, wherein when the RTC device is detected, an RTC device distance is determined, the RTC device distance being the distance between the RTC device and the detection system, and Wherein the entity is determined to be a human being when it is determined that the entity distance and the RTC device distance are within a threshold distance difference of each other.

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