A frequency detection device
By installing a frequency detection device inside the television set, the leaked high-frequency electromagnetic waves are captured and analyzed, thus solving the health risks associated with electromagnetic waves leaking from the tuner. This enables real-time monitoring and alarm functions, ensuring user safety.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- SHANGHAI PINYU ELECTRONIC TECH CO LTD
- Filing Date
- 2025-08-01
- Publication Date
- 2026-07-21
Smart Images
Figure CN224536078U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the field of electromagnetic wave frequency measurement technology, and in particular to a frequency detection device. Background Technology
[0002] Electromagnetic waves (EMF) are oscillating particle waves that propagate in space from in-phase and mutually perpendicular electric and magnetic fields. They are essentially a form of energy propagation, and their generation is related to electron motion (such as changes in current, charge acceleration, etc.).
[0003] Currently, LCD / LED / OLED TVs are widely used, and CRT TVs have been phased out in most areas. However, CRT TVs still exist in some underdeveloped regions and remote mountainous areas. In these areas, both LCD / LED / OLED and CRT TVs rely primarily on built-in tuners to receive radio waves from the air (e.g., via antennas or cables) and tune to the user-selected channel. However, tuners also pose a potential risk of high-frequency electromagnetic wave leakage, such as local oscillator (LO) leakage in the 500MHz-1GHz frequency band and harmonic radiation during signal amplification. This high-frequency electromagnetic wave leakage poses potential health risks to users of LCD / LED / OLED or CRT TVs at close range.
[0004] Therefore, there is an urgent need to develop a frequency detection device that can monitor in real time and with high sensitivity whether the tuner is leaking high-frequency electromagnetic waves and issue a warning. Utility Model Content
[0005] This invention addresses the technical problem of potential high-frequency electromagnetic wave leakage from the tuners built into existing LCD / LED / OLED or CRT television displays. It proposes a frequency detection device.
[0006] In a preferred embodiment of this utility model, a frequency detection device is provided, which is disposed inside a television set. The frequency detection device includes:
[0007] The first tuning unit is used to receive terrestrial wave, cable or satellite radio frequency broadcast television signals and tune the television set to the corresponding channel.
[0008] A broadband microstrip antenna unit is positioned adjacent to the first tuning unit and is used to capture high-frequency electromagnetic waves leaked from the first tuning unit.
[0009] The second tuning unit is connected to the broadband microstrip antenna unit and is used to perform spectrum analysis on the high-frequency electromagnetic waves captured by the broadband microstrip antenna unit and output a radiation intensity analog signal.
[0010] A control unit, connected to the second tuning unit, is used to convert the analog radiation intensity signal into a digital signal. If the radiation intensity corresponding to the digital signal exceeds a preset threshold, the control unit triggers a warning message to be displayed on the television screen.
[0011] The frequency band coverage of the high-frequency electromagnetic waves leaked by the first tuning unit is 500MHz–1GHz;
[0012] The location of the broadband microstrip antenna unit is no more than 1 cm away from the location of the first tuning unit.
[0013] Preferably, the high-frequency electromagnetic wave leaked by the first tuning unit is a high-frequency electromagnetic wave leaked through the local oscillator.
[0014] Preferably, the broadband microstrip antenna element is a dual-polarization element that combines horizontal and vertical polarization.
[0015] Preferably, the broadband microstrip antenna unit adopts Rogers RO4350B double-layer board technology with a total thickness of 0.8mm. The back side is fully copper-clad and the defect ground structure is etched to suppress back radiation.
[0016] Preferably, the second tuning unit includes a low-noise amplifier, an adjustable bandpass filter, and a zero-IF I / Q demodulation link.
[0017] Preferably, the second tuning unit maintains a lateral distance of not less than 5mm from the first tuning unit in its layout, and electromagnetic isolation is achieved through a metallized through-hole fence.
[0018] Preferably, the control unit includes an analog-to-digital converter.
[0019] Preferably, the preset threshold for the radiation intensity is -40 dBm.
[0020] Compared with the prior art, the present invention can achieve the following beneficial effects:
[0021] This application discloses a frequency detection device, which includes a first tuning unit, a broadband microstrip antenna unit, a second tuning unit, and a control unit. After the television is powered on, the first tuning unit first locks the 40MHz–1GHz broadcast television signal from terrestrial wave, cable, or satellite radio frequency to the channel selected by the user. At the same time, its tuning local oscillator radiates a 500MHz–1GHz local oscillator leakage into space. A broadband microstrip antenna unit, closely attached to the first tuning unit and spaced no more than 1 cm from it, instantly captures the leakage and responds across the entire frequency band. The coupled high-frequency electromagnetic wave energy is then sent to the second tuning unit. The low-noise amplifier, adjustable bandpass filter bank, and zero-IF I / Q demodulation link within the second tuning unit perform scanning measurements of the power at each frequency point within the 500MHz–1GHz range and calculate the full-band radiation intensity. The simulated radiation intensity signal is then sent to the control unit. The control unit converts it into a digital signal using an on-chip high-speed ADC and compares it with a -40dBm reference threshold that dynamically adjusts with ambient temperature. If the measured value is higher than the threshold, the television screen is immediately triggered to issue a local alarm, thus achieving closed-loop real-time monitoring from signal reception, leakage capture, spectrum analysis to threshold judgment and human-computer interaction. Attached Figure Description
[0022] The preferred embodiments will now be described in a clear and easy-to-understand manner, with reference to the accompanying drawings, to further explain the above-mentioned characteristics, technical features, advantages, and implementation methods.
[0023] Figure 1 A schematic diagram of a frequency detection device according to one embodiment of the present invention is shown.
[0024] Figure 2 A schematic diagram of the structure of the second tuning unit of a frequency detection device according to one embodiment of the present invention is shown. Detailed Implementation
[0025] The following provides a more detailed description of various aspects of this utility model.
[0026] Unless otherwise defined or stated, all technical and scientific terms used herein have the same meaning as are familiar to those skilled in the art. Furthermore, any methods and materials similar to or equivalent to those described herein may be applied to the methods of this invention.
[0027] Other aspects of this invention will be apparent to those skilled in the art from the disclosure herein.
[0028] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the specific implementation methods of this utility model will be described below with reference to the accompanying drawings. Obviously, the drawings described below are merely some embodiments of this utility model. For those skilled in the art, other drawings and other implementation methods can be obtained based on these drawings without any creative effort.
[0029] It should also be noted that the illustrations provided in the following embodiments are only schematic representations of the basic concept of this application. The drawings only show components related to this application and are not drawn according to the actual number, shape, and size of the components in the actual implementation. In the actual implementation, the form, quantity, and proportion of each component can be arbitrarily changed, and the layout of the components may also be more complex. For example, the thickness of the elements in the drawings may be exaggerated for clarity.
[0030] Example 1
[0031] As attached Figure 1-2 As shown, this utility model implements a frequency detection device 5, which is disposed inside a television set. The frequency detection device 5 includes:
[0032] The first tuning unit 1 is used to receive terrestrial wave, cable or satellite radio frequency broadcast television signals and tune the television set to the corresponding channel.
[0033] A broadband microstrip antenna unit 2 is positioned adjacent to the first tuning unit and is used to capture high-frequency electromagnetic waves leaked from the first tuning unit 1.
[0034] The second tuning unit 3 is connected to the broadband microstrip antenna unit 2 and is used to perform spectrum analysis on the high-frequency electromagnetic waves captured by the broadband microstrip antenna unit 2 and output a radiation intensity analog signal.
[0035] Control unit 4, connected to the second tuning unit 3, is used to convert the analog radiation intensity signal into a digital signal. If the radiation intensity corresponding to the digital signal exceeds a preset threshold, the control unit triggers a warning message to be displayed on the television screen.
[0036] The frequency band coverage of the high-frequency electromagnetic waves leaked by the first tuning unit 1 is 500MHz–1GHz;
[0037] The location of the broadband microstrip antenna unit 2 is no more than 1 cm away from the location of the first tuning unit.
[0038] Preferably, the high-frequency electromagnetic waves leaked by the first tuning unit 1 are high-frequency electromagnetic waves leaked through the local oscillator. It should be noted that the first tuning unit 1 is an integrated silicon tuner commonly used in televisions (e.g., the Silicon-Tuner Si2151 series silicon tuner), which receives terrestrial, cable, or satellite radio frequency broadcast television signals through a coaxial port and tunes the television to the user-selected channel through a phase-locked loop-voltage-controlled oscillator (PLL-VCO) network. During the tuning process, the local oscillator signal in the PLL-VCO network inevitably radiates outward in the 500MHz–1GHz frequency band due to discontinuities in PCB traces or unavoidable shielding gaps, forming high-frequency electromagnetic waves leaked by the local oscillator.
[0039] Preferably, the broadband microstrip antenna unit 2 is a dual-polarized unit with both horizontal and vertical polarization. It should be noted that the broadband microstrip antenna unit 2 is a dual-polarized microstrip patch array, composed of two orthogonally placed butterfly-fractal composite patches. Each patch is etched with a second-order Koch fractal curve and slotted to extend the bandwidth, with a -10dB impedance bandwidth covering 500MHz–1GHz. The broadband microstrip antenna unit 2 is mounted in an L-shaped layout on the top surface of the shield of the first tuning unit, with its geometric center ≤1cm horizontally from the local oscillator VCO chip of the first tuning unit. It is used to capture the 500MHz–1GHz local oscillator leakage high-frequency electromagnetic waves from the first tuning unit in a dual-channel manner with both vertical and horizontal polarization, and outputs the dual-polarized signals after in-phase superposition through a three-in-one Wilkinson power divider / combiner.
[0040] It should be noted that the broadband microstrip antenna unit and the first tuning unit are positioned no more than 1 cm apart. The main reasons are as follows: First, the high-frequency electromagnetic waves leaked from the first tuning unit (500MHz–1GHz local oscillator leakage) are weak radiated signals, and their energy attenuates rapidly with increasing propagation distance. The broadband microstrip antenna unit needs to be close to the first tuning unit to effectively capture the leaked high-frequency electromagnetic wave energy, avoiding excessive signal attenuation due to excessive distance, and ensuring that the subsequent second tuning unit can accurately perform spectrum analysis and power measurement on the weak signal. Second, the local oscillator leakage from the first tuning unit is near-field radiation (mainly radiated through PCB trace discontinuities or shielding gaps). Within 1 cm of the radiation source, the electromagnetic wave is dominated by a magnetic field component, with concentrated energy and strong directionality. The broadband microstrip antenna unit can more efficiently couple magnetic field energy within this near-field range, especially with its dual-polarization design (horizontal polarization + vertical polarization), which can maximize the coverage of the polarization direction of the leaked electromagnetic wave, improving capture efficiency. Finally, the fact that the distance between the broadband microstrip antenna unit and the first tuning unit is no more than 1 cm is conducive to the compact arrangement of internal components of the television.
[0041] Preferably, the broadband microstrip antenna unit 2 adopts Rogers RO4350B double-layer board technology with a total thickness of 0.8mm. The back side is fully copper-clad and the defect ground structure is etched to suppress back radiation.
[0042] Preferably, the second tuning unit 3 includes a low-noise amplifier 6, an adjustable bandpass filter 7, and a zero-IF I / Q demodulation link 8. It should be noted that the second tuning unit is directly connected to a broadband microstrip antenna unit via a 50Ω microstrip line, used for real-time spectrum analysis of the superimposed high-frequency electromagnetic waves and outputting a full-band radiation intensity analog signal; wherein, the second tuning unit includes, along the signal path, the following components in sequence:
[0043] a) Low-noise amplifier 6 (LNA), noise figure ≤1.1dB, gain 20dB, used to boost weak leakage signal levels;
[0044] b) Adjustable bandpass filter 7, a 500MHz–1GHz SAW filter, used to suppress out-of-band noise;
[0045] c) Zero-IF I / Q demodulation link 8, including an I / Q demodulator (such as ADL5380) and an on-chip local oscillator (generated by the control unit DDS), is used to directly downconvert 500MHz–1GHz signals to baseband I / Q signals, and outputs an analog voltage that is linearly related to the radiated power through a root mean square detector.
[0046] Preferably, the second tuning unit 3 maintains a lateral distance of not less than 5mm from the first tuning unit in its layout, and electromagnetic isolation is achieved through a metallized through-hole fence.
[0047] Preferably, the control unit 4 includes an analog-to-digital converter. It should be noted that the control unit 4 integrates an ARM Cortex-M0+ core and a 12-bit successive approximation analog-to-digital converter (ADC) to convert the full-band radiation intensity analog signal into a digital signal at a rate of 1 kS / s, and executes a temperature-compensated threshold decision algorithm in the firmware. If the radiation intensity corresponding to the digital signal exceeds a preset threshold of -40dBm, the control unit sends an emergency OSD command to the TV's main SoC via the HDMI-CEC bus, triggering the TV screen to overlay a semi-transparent red warning frame in the upper right corner, and simultaneously driving the onboard buzzer to emit a 1kHz intermittent sound. If the radiation intensity continues to rise to >-20dBm, the control unit pulls down the TV_PWR_ON signal to put the entire unit into a safe shutdown state.
[0048] Preferably, the preset threshold for the radiation intensity is -40 dBm.
[0049] During use, after the television is powered on, the first tuning unit 1 first locks the 40MHz–1GHz broadcast television signal from terrestrial waves, cable or satellite radio frequency to the channel selected by the user. At the same time, its tuning local oscillator radiates 500MHz–1GHz local oscillator leakage into space. The broadband microstrip antenna unit 2, which is closely attached to the first tuning unit 1 and is no more than 1 cm away from it, immediately captures the leakage and responds across the entire frequency band. Then, the coupled high-frequency electromagnetic wave energy is sent to the second tuning unit 3. The low-noise amplifier 6, the adjustable bandpass filter 7, and the zero-IF I / Q demodulation link 8 in the second tuning unit 3 perform scanning measurements of the power at each frequency point in the 500MHz–1GHz range and calculate the full-band radiation intensity. Then, the simulated radiation intensity signal is sent to the control unit 4. The control unit 4 converts it into a digital signal through an on-chip high-speed ADC and compares it with a -40dBm reference threshold that is dynamically adjusted according to the ambient temperature. If the measured value is higher than the threshold, the TV screen is immediately triggered to issue a local alarm, thereby realizing closed-loop real-time monitoring from signal reception, leakage capture, spectrum analysis to threshold judgment and human-computer interaction.
[0050] Based on this application, those skilled in the art will understand that one aspect described herein can be implemented independently of any other aspect, and two or more of these aspects can be combined in various ways. For example, any number and aspect set forth herein can be used to implement the device and / or practice the method. Additionally, this device and / or practice the method can be implemented using other structures and / or functionalities besides one or more of the aspects set forth herein.
[0051] It should be noted that the above embodiments can be freely combined as needed. The above description is only a preferred embodiment of this utility model. It should be pointed out that for those skilled in the art, several improvements and modifications can be made without departing from the principle of this utility model, and these improvements and modifications should also be considered within the protection scope of this utility model.
[0052] All documents mentioned in this invention are incorporated herein by reference as if each document were individually incorporated by reference. Furthermore, it should be understood that after reading the foregoing description of this invention, those skilled in the art can make various alterations or modifications to this invention, and these equivalent forms also fall within the scope defined by the appended claims.
Claims
1. A frequency detection device, characterized in that, The frequency detection device is disposed inside the television set, and the frequency detection device includes: The first tuning unit is used to receive terrestrial wave, cable or satellite radio frequency broadcast television signals and tune the television set to the corresponding channel. A broadband microstrip antenna unit is positioned adjacent to the first tuning unit and is used to capture high-frequency electromagnetic waves leaked from the first tuning unit. The second tuning unit is connected to the broadband microstrip antenna unit and is used to perform spectrum analysis on the high-frequency electromagnetic waves captured by the broadband microstrip antenna unit and output a radiation intensity analog signal. A control unit, connected to the second tuning unit, is used to convert the analog radiation intensity signal into a digital signal. If the radiation intensity corresponding to the digital signal exceeds a preset threshold, the control unit triggers a warning message to be displayed on the television screen. The frequency band coverage of the high-frequency electromagnetic waves leaked by the first tuning unit is 500MHz–1GHz; The location of the broadband microstrip antenna unit is no more than 1 cm away from the location of the first tuning unit.
2. The frequency detection device as described in claim 1, characterized in that, The high-frequency electromagnetic wave leaked by the first tuning unit is a high-frequency electromagnetic wave leaked through the local oscillator.
3. The frequency detection device as described in claim 2, characterized in that, The broadband microstrip antenna element is a dual-polarization element that combines horizontal and vertical polarization.
4. The frequency detection device as described in claim 3, characterized in that, The broadband microstrip antenna unit adopts Rogers RO4350B double-layer board technology with a total thickness of 0.8mm. The entire back side is copper-clad and the defect ground structure is etched to suppress back radiation.
5. The frequency detection device as described in claim 4, characterized in that, The second tuning unit includes a low-noise amplifier, an adjustable bandpass filter, and a zero-IF I / Q demodulation link.
6. The frequency detection device as described in claim 5, characterized in that, The second tuning unit maintains a lateral distance of not less than 5mm from the first tuning unit in its layout, and electromagnetic isolation is achieved through a metallized through-hole fence.
7. The frequency detection device as described in claim 6, characterized in that, The control unit includes an analog-to-digital converter.
8. The frequency detection device as described in claim 7, characterized in that, The preset threshold for the radiation intensity is -40 dBm.