Simple fm circuit. Another Simple AM Radio Antenna Booster Circuit.
Simple fm circuit Run the simulation file and observe the waveforms. The T2 transistor together with the R1 resistor, the coil L the variable capacitor C and internal capacitances of the T1 transistor, comprises the so-called Kolpitz oscillator. In this article, you will see how to make an FM receiver. Simple Fm Receiver Circuits Using Transistors And Ic Easyeda FM Modulation/de-modulation Circuit: I got the idea for this circuit from one of my professors. Simplest Fm Receiver Circuit How To Build And Use One. Here two This simple fm radio receiver circuit consists of a regenerative rf stage, TR1, followed by a two of three-stage audio amplifier, TR2 to TR4. This FM Transmitter circuit needs very less components. Voici les choses dont vous avez besoin pour faire un circuit d’émetteur FM: Batterie 9v. This makes it accessible for hobbyists and DIY enthusiasts. The circuit is nothing but a classic single transistor oscillator operating in the VHF region. The first stage of the circuit is a preamplifier stage based on transistor Q1. Homemade simple FM transmitter circuit diagram. Simple FM Transmitter Circuit. The circuit has a frequency range that can be tuned between 88 and 108 MHz, and is quite stable, and Simple FM Remote Control Circuit. Yet Another Simple Mw Receiver Details Hackaday Io. \$\endgroup\$ – Audioguru. The Simplest F M Transmitter Ever Made Circuits Diy. In telecommunication, frequency modulation (FM) transfers information by varying the frequency of the carrier wave according to discriminator—a circuit or device in which amplitude variations are de- rived from frequency or phase varia- tions. Circuit and Working. It operates at a voltage range of 6V to 12V and uses 2N3904 NPN transistors as the key components. The Oscillation circuit could be made with the help of Transistor 2N3904, Inductor and the variable capacitor. Most of the available FM transmitter circuits have, in my opinion, a Simple FM Radio (Updated): Simple and powerful fm radio with easy to find parts. Building your own FM radio circuit can be a rewarding project, but it can also come with its fair share of challenges. The circuit enables transmiting music signals Medium wave and short wave were the main broadcast radio bands until the advent of FM. It's simple design makes it ideal for a pocket sized FM receiver. The audio output of the receiver is amplified through LM386 amplifier chip that can In this tutorial, we will construct a very entertaining circuit simple FM transmitter circuit. In telecommunication, frequency modulation transfers the data by changing the frequency of the carrier wave as per the message signal. In this article, we will guide you through the process of constructing an Simple FM Transmitter Circuit Diagram. I needed to replace the 4. Simple Voice FM Transmitter Circuit designed by using single NPN BC547 Transistor. **Enclosure (Optional):** - If desired, place the circuit in an enclosure to protect it and make it more portable. Simplest Homemade Electric Guitar. Building a homemade FM transmitter circuit using common electronic components is an exciting project that can be easily accomplished. The offered system enables us to generate an FM transmitter, which includes an amplified microphone circuit, with compact dimensions (23 × 41 mm) that functions within a frequency range between 70 and 110 MHz. This is a very high frequency (VHF) circuit, so you will want to use Fm Receiver Circuit. This project was designed to be mounted on a PCB, however you don’t have to. This article describes how to build a simple stereo FM Radio Receiver Circuit without tuning components such as inductors, variable The Circuit Diagram of this Simple FM Transmitter is shown in the image below. So, the first stage of the circuit is a preamplifier stage based on transistor Q1. The circuit is self explanatory, just the inclusion of a general purpose BC559 transistor along with a few inexpensive passive components can be See more Here’s a simple FM receiver circuit with minimum components for local FM reception. It may be tuned anywhere in the FM band. 5KΩ) sets the collector current and R1 (47KΩ) provides the necessary collector-to-base bias. Org. 10kΩ Resistor 1. Build very simple and easy to find parts. So this circuit have two resonance circuits and also two trimmers. Cette section vous montrera comment créer le circuit d’émetteur FM DIY le plus simple qui fonctionne parfaitement. 1 Watt Fm Transmitter Project. The circuit has a central RF oscillator NPN transistor BF494 (substitute: BF194). Simple Am Receiver Circuit. We can use it to send all sound to the FM receiver. Wireless & RF Design: 2: Sep 24, 2024: P: PCB Review Request: STM32 based FM Radio Receiver: PCB Layout , EDA & Simulations: 1: Jul 22, 2024: H: I want circuit for FM Radio Transmitter and FM Radio Receiver: Wireless & RF Design: 9: Dec 16, 2009 Simple Fm Transmitter Circuit Homemade Diagram. 43 you can se the electronic circuit of an extremely simple direct FM receiver. FM Jammer Circuit Explanation: The variable capacitor C1 and L1 will constitute the tank circuit which will produce the high frequency signal, the capacitor C1 is variable With a matching antenna, the FM transmitter circuit shown here can transmit signals up to a range of 2 kilo meters. 1) FM Transmitter Circuit Description. – Internal the integrated circuit TDA7000 includes: R. Antenna catches fm waves, first transistor works as oscillator. The Simplest FM Transmitter Ever Without Coil/inductor: I made this project three years ago, and it works perfectly. However a simple homemade FM remote control can be made by modding your existing FM radio as the receiver part. For a hobbyist circuit, that FM will be quite sufficient to broadcast a signal to an ordinary FM receiver 1. Variable capacitor C sets the circuit’s Potentiometer P1 should subsequently be adjusted to allow the ideal FM reception of the transmitter. It converts our sound signal into a radio signal so that it can be picked by every FM radio and television that is tuned at the same frequency. An FM transmitter circuit is a low-power radio transmitter that allows any device 3 Volt Easy Diy Fm Receiver By Ta2003 I C Circuits. This stage is served by Q1 (BC108). I've never done anything RF related on my own (appart from a very simple AM receiver, based on a germanium diode), so I found interesting and exciting building a simple FM circuit, and see how it works. But we have the constraint called noise. How to Make FM Radio Circuit In this article, you will learn how to make an FM radio circuit easily at home. The first stage is the preamplifier stage where audio input signal is amplified before modulation. Circuit Zone Com Electronic Kits Projects Schematics Diy Electronics. In the context of an FM receiver circuit, it illustrates the arrangement of transistors and other components that enable the receiver to Simple Slope Detector – Circuit diagram and its Characteristics: The circuit diagram of a simple slope detector is depicted in Fig. Here, the transistor T2, resistor R1, variable capacitor C, coil L, and transistor T1’s capacitance form a Colpitts oscillator. Here is a convenient quality sensitive FM recipient circuit or FM tuner circuit. And it's recommended to use a proper IC based FM radio receiver module if you intend to use this for day to day application. The circuit works around the TDA 7021T IC which is an FM radio receiver IC. The following AM booster circuit can significantly enhance poor AM broadcast reception if that is a problem for you. You can use a 9v to 12v DC power supply for this circuit. When it This article shows you how to build a very simple FM transmitter from thirteen components, a Printed Circuit Board (PCB) and a 9v battery. When the audio signal is from the microphone, it converts the signal into an electrical signal and then that signal Build a compact FM transmitter to experiment with RF circuits. Fig. The transmission frequency of the circuit is around 100 Mhz, and can be adjusted by adjusting the 20 PF trimmer capacitor. Thus, it’s easy to create. F. A simple FM transmitter circuit uses Radio Frequency Transmission to transfer the medium or low-power FM signal. Troubleshooting Your FM Radio Circuit . With a matching antenna, this transmitter can attain a range of around 200 meters. A coil takes care of the output frequency. It is a simple circuit that you can assemble with your commonly available components and 3 transistors. Note: if Fm broadcasts are weak or far away in your area, please use v2 circuit in troubleshooting step! Thank you. In the meantime, you may also read about our 2KM FM transmitter circuit and also if you got free time, try our 200M FM transmitter as well. We have published lots of radio transmitter circuits, which will help you learn a lot about basic communication electronics. In some areas 3 stages of audio amplification may not be necessary, in which case TR3 and its This video explains what frequency modulation (FM) is and shows a simple low powered FM radio transmitter circuit you can build. Generally, the FM transmitter uses VHF radio frequencies of 87. The range of the transmitter is about 50 m. 2. Simple Fm Transmitter Electronics Lab Com. Then this very simple FM transmitter will sound muffled (no high audio frequencies) on any FM radio. Circuit shown here can be used to jam FM radios in its vicinity. Personally, I was amazed by how well it worked, considering the actual receiver had only one transistor. 36 SWG wire 2. One Transistor Fm Receiver Electronic Schematic Diagram. Hence, It is an enjoyable project to create an FM transmitter and broadcast our own signaling. This guide will show you how to build your own remote control system for your home! We'll use a regular FM radio (with a slight modification) to receive the signal and a simple transmitter you can build yourself. 5 km of distance, using a suitable antenna, powered by a power supply or a 12Vdc battery. You can adjust the frequency to any required frequency of FM station. Building your own FM transmitter is a great way to When integrated with a loudspeaker and an amplifier (for example an LM386 amplifier), this simple FM radio circuit could very easily be constructed into a extremely sleek and stylish pocket radio. Ultimate Guide: Building a Powerful 2. With this one I didn't get a nice sinusoidal oscillations. Simple FM transmitter circuit made with few easily available components, This Frequency Modulation reaches several meters to kilo meter with low power transmitter circuit. The transistor Q1 and Q2 forms a classic high sensitive preamplifier stage. Last Updated on March 16, 2024 . This is a simple FM transmitter, with great range, being able to reach more than 2. This is a collector-to-base biased amplifier stage where resistor R3 (1. The proposed simple radio circuit works with approximately 10 mA from a 9-volt battery. If you’re experiencing issues with your radio, here are some troubleshooting steps to help you identify and fix the problem. I downloaded 3 Simple schematics shown with one BF 494 transistor ---another with TWO BF 494 transistors--and a third ---with amplifier --similar circuit all these I carefully built ( home made circuit)--none appear to work at all ---dead silent --DESPITE being surrounded by many powerful FM stations-- Description. The performance and working of the wireless audio transmitter circuit depend on the induction coil & variable capacitor, this circuit oscillates up to 100 MHz and you can tune and adjust the oscillating frequency by varying Trim Capacitor. The IC requires just barely any external parts and the necessary voltage is just 3 Explication du circuit du récepteur FM Voici un simple récepteur FM avec des composants minimaux pour la réception FM locale. Check the Power Supply 4. Internal freq The circuit is extremely easy, and is based on the SN7413 chip. In order to transmit the audio signal to the longer distance, we use modulation technique. Two Transistors Fm Transmitter Envirementalb Com. That design wasn't meant for passing frequencies high enough to be able to pass an audio file, e. Circuit Diagram In this DIY, we are demonstrating a project of a Simple “FM Transmitter Circuit”. No special coils or uhf transistors. Vk3ye On Pic. Remember that building an FM radio receiver is an educational project, and the performance may vary. 0 MHz to transmit & receive the FM signal. Circuit is very simple. The circuit is a simple 88-108 MHz VHF FM transmitter circuit. The circuit we use is based on a proven Australian design. But they are still popular as they have more channel space than FM stations and offer longer range coverage, especially at night via the ionosphere. The radio circuit diagram above is that of a straightforward FM receiver. Circuit Diagram In this DIY tutorial, we will discuss a simple FM transmitter. The simple FM transmitter is built around low-power audio amplifier using LM386 (IC1), transistor PN2222A (T1), 30MHz crystal (XTAL1), varactor diode 1SV149 (D1) and a few other components. This is perhaps one of the simplest and smallest FM receivers for receiving local FM stations. The receiver will (treble boost) and all FM radios produce matched de-emphasis (treble cut). Let FM Radio Jammer Circuit Diagram: Circuit Diagram of Simple FM Radio Jammer – ElectronicsHub. In this circuit, C3 is a 1 – 40 pf trimmer capacitor, and L1 is 8 to 10 turns of hookup wire of 22 measure twisted on a 6mm structure. It is a NPN transistor which is basically used for signal and voltage amplification purposes. 5KM FM Transmitter with 2N3866 Transistor and PCB. amplifier/limiter, Quadrature Demodulator FM Detector, Phase demodulator, Mute This just another one, a simple two transistor FM transmitter. This circuit is to create a simple, no hassle, use the equipment less. In some areas 3 stages of audio amplification may not be necessary, in which case TR3 and its associated components can be omitted and the free end of capacitor C5 connected to the collector of TR2. Simple Fm Radio Circuit Using A Single Transistor Homemade Projects. Microchip microcontroller users is quite a useful experiment to work you need a Pic18f452 development Board this way, small-sized double-sided printed circuit board drawing a lot of property has been added max232 rs232 . 2 Small Fm Transmitter Circuits Explained. It includes 3 blocks; modulator / oscillator, 2 stage 500mW VHF amplifier and LED based power meter. In other words, the circuit uses two tuned circuits which are tuned to two different frequencies. This circuit is based on two npn transistor of 2N2222 which is low power amplifier. The circuit is built around a low-power audio amplifier using LM386 (IC1), transistors 2N3904 (T1 and T2) and 2N3866 (T3), 24MHz crystals (XTAL1 and XTAL2), rectifier diode IN4007 (D1), signal diode IN4148 (D2) and a few other components. Circuit Explanation. Now, some components are required when making a simple FM Radio, and they are as follows: LM386. 52(a). Fm receiver circuit diagram using transistor. Working principle of the circuit is very simple and straight forward. Simple Fm Transmitter Circuit. Presented below is a simple FM receiver circuit with minimal components for local FM reception. 1 Comment “ Simple FM Transmitter Circuit 88-108 MHz ” Electronics Circuits 2016/05/02. The coil has to made by yourself. 5 to 108. To make the above circuit self-contained, an additional transistor stage may be introduced for enabling the radio to play the music loudly over a small loudspeaker. How To Build A Simple FM Radio . 3. This FM This is basically a simple DIY hobby circuit and you can try it in your home with minimal components. This is a regenerative Fm radio. The following “circuit” is all we need for creating an FM waveform consisting of a 10 MHz carrier and a 1 MHz sinusoidal baseband signal: A simple and effective FM demodulation technique involves a high-pass filter (for FM-to-AM conversion) followed by an AM demodulator. It has a range of about 20 m Jeff Heidbrier, in Texas, has come up with a pretty nice printed circuit board design for this simple FM Stereo Transmitter. It is basically a VHF Colpitts oscillator capable of transmitting sound or music to any standard FM receiver. The layout is intended to accept resistors mounted vertically, as shown in the photograph, so you have some flexibility in that you can use any size from 1/8 up to about 1/2 watt sizes. Also, the Broad-Band FM receiver circuit gives an efficient signal transmission range and excellent frequency stability. I have found the circuit of this project in a book I bought eighteen years ago when I was in high school. Inductor L1 is a three-turn coil made with 20SWG wire that has 8mm diameter with half-turn taping. Despite its small size and inconspicuous design, it can be used to transmit radio signals over a wide Without their proper construction and alignment, the circuits do not perform well. . Check out this article to learn how to build an Simple FM Receiver Circuit. 7. We design a simple multipurpose FM transmitter circuit by using two NPN transistors and a few easily available components. 100m Simple Fm Transmitter. Working Explanation. This FM transmitter constructed very easily. We modulate the frequency of the signal. Suppose you’re looking at how to design and build the simplest FM receiver circuit. The size of a standard pencil is additionally 6mm so you can utilize a round pencil as a structure to wind the curl. A circuit diagram is a graphical representation of an electrical circuit. The Simplest Fm Receiver Mikroe. If you are using an The circuit is tuned to different stations using tuning capacitor C5, and potentiometer P1 should be adjusted to enable ideal FM reception. 5V battery to the FM transmitter circuit board as an input supply. After soldering all components, I connect a 1. Additionally, you’ll need it to receive locally available signals This FM receiver circuit uses CXA1019 is a bipolar silicon monolithic FM/AM radio receiver IC from Sony. This Slope Detector circuit consists of a tuned circuit which is slightly detuned from the carrier frequency ω c. A Simple FM radio circuit diagram is a perfect way for anyone to get started in the world of radio electronics. Projects Contests Teachers Simple FM Radio (Updated) By mkpeker in Circuits Electronics. When integrated with a loudspeaker and an amplifier (for example an LM386 amplifier), this simple FM radio circuit could very easily be constructed into a extremely sleek and stylish pocket radio. FM transmitters are used to transmit audio signals wirelessly, allowing users to listen to their favorite radio stations without being limited by cables. The Circuit Diagram Of A Low Cost Mobile Fm Transmitter Scientific. Microphone ou toute autre entrée audio. input stage, Mixer, Local oscillator, I. 2kΩ Resistor 4. Transistor Q1 is a high gain audio amplifier that amplifies the sound detected by the electret microphone. Antenne. In the telecommunication, the frequency modulation (FM) transfers the information by varying the frequency of the carrier wave according to the message signal. Step 2: Building. The output of Q1 is fed into the frequency modulating circuit created by transistor Q2, inductor L1, and variable capacitor C5. By understanding and building this schematic, individuals can gain a hands-on understanding of how FM Receiver Circuit Explanation:. 7kΩ Well, with a Simple FM radio circuit diagram, you can make it happen! This easy-to-follow diagram can help you build your own homemade radio from scratch without needing any special knowledge. This mini FM transmitter circuit will broadcast FM signal to considerably long distance. Slope Both demodulators are simple to construct using discrete components and offer good levels of performance This is simple FM Wireless Microphone circuit diagram. In this project, you will learn “How to make FM Transmitter Circuit” with suitable components and How it Works. When combined with a loudspeaker and amplifier, such as an LM386 amplifier, this simple FM radio circuit can be made into a very sleek and compact pocket radio. It shows the components and connections between them in a clear and organized manner. Under this heading, we are discussing the circuit operation of the “Simple FM transmitter”. It can be built on a breadboard or soldered to a Perf board. Receiver consists of a regenerative rf stage, TR1, followed by a two of three-stage audio amplifier, TR2 to TR4. This FM radio circuit is highly efficient with a clear audio output. You can develop your FM receiver circuit that’s small enough to fit in your pocket. The circuit is powered by 9V battery which makes it easily portable. It requires a small component count, such as a satellite receiver, standard FM receiver, wire antenna, and amplifier chip. Circuit Diagram Components Needed. So we’ve seen the circuit diagram and how to assemble a long-range FM transmitter. It has two stages served by two transistors Q1 and Q2. Radio is very sensitive and selective. If you are looking for some FM Radio Receiver IC Then the RDA5807 or TEA5767 are some of the ICs which are easily available in the market and you can make simple FM receiver circuit with easily available parts and schematics. AM receivers are also simple and easy to build. - Turn on the FM receiver and tune it to a known FM station. 22. With this circuit, you will be able to transmit your voice over short distances using basic components. 5turns only in 5mm diameter ferrite rod. Adjust the antenna length for better reception. 4414 Views December 19, 2023 Kiran Saleem . The Colpitts oscillator comprises Transistor BF495 T2, a 10k resistor R1, coil L, a 22pF You just have to connect the arrow head side of the above explained LC circuits with the gate of the FET Q1 in the below shown circuit. Transistor BF495 (T2), together with a 10k resistor (R1), To make the Simple FM Transmitter, we are using the condenser microphone that provides the audio signal. Or it may be tuned outside the commercial M band for greater privacy. Start building this high range FM transmitter and see how your output comes. Last Updated on November 13, 2024 by Admin Leave a Comment. FM Transmitter Circuits. The circuit has many uses, but is popular as a detector in FM receivers. 500Hz+, so I built this by modifying the carrier and signal frequencies, using only the Di The circuit is simple and easy to make. This circuit is capable of producing the loud sound Read More »How to Make FM Radio Circuit This simple fm radio receiver circuit consists of a regenerative rf stage, TR1, followed by a two of three-stage audio amplifier, TR2 to TR4. In some areas 3 stages of audio amplification may not be necessary, in which case TR3 and its associated components can be omitted and the free end of capacitor The FM transmitter is a single transistor circuit. FM is The FM crystal radio schematic is a simple yet effective design that allows users to listen to FM radio stations using just a few components. Le transistor BF495 (T2), associé à une résistance 10k (R1), une bobine L, un condensateur variable 22PF (VC) et des capacités internes du transistor BF494 (T1), comprend l'oscillateur Colpitts. The proposed circuit is a straightforward to construct 5 km range FM Transmitter. This FM radio receiver circuit is very simple to build and is powered by just a single 1. The transmitter can be simply made by assembling a few electronic components. It could be picked up by a straightforward FM receiver a few tens of yards apart. Especially with this circuit, you need not damage your own boost converter or use a mower to set up the circuit correctly. The circuit is powered by a 9V power supply. com website. With a matching antenna, the FM transmitter circuit shown here can transmit signals up to a range of 2 kilo meters. Description. Note: This circuit diagram has been taken from circuitstoday. The circuit diagram of the 96MHz crystal-locked simple FM transmitter is shown in Fig. The complete circuit can be powered using a 9V Battery. A very stable and simple FM transmitter circuit is given here. This circuit is basically a combination of a microphone preamplifier & an FM transmitter. Simple FM transmitter circuit diagram. Step 4: Demo & Testing - Last Updated on March 16, 2024 . Introduction. (Of course this means you must modify your FM radio to be We have looked at how FM receivers work and presented a fairly simple working design. The Theory Behind the Circuit The most common type of FM transmitter circuit is a simple frequency modulated (FM) circuit that is used to generate and radiate an FM signal on the desired frequency using a single transistor (or other active device). Condensateur variable. In this section, we discuss how to build your simple FM radio. Wheel of Fortune Game Circuit. Microchip Development Test Board PIC18F452. Also, I simply connect an RC Antenna for large distance transmission. You could A FM transmitter circuit diagram is a visual representation of the electronic components and connections used to create a radio frequency Easy to Build: FM transmitter circuits can be relatively simple to build, with many designs available online and in electronics magazines. The FM TX is a solitary transistor circuit. It also has a capacitor microphone which picks up very weak sound signals. Another Simple AM Radio Antenna Booster Circuit. Fig 1: Repairing a radio FM receiver. Le De tous les émetteurs FM Component values of L1 (207nH) and CV (8-28 pF) are chosen to resonate somewhere in the FM broadcast band (88 MHz -to- 108 MHz here). 1 Outils de production de circuits d’émetteurs FM. Inducteur The tuned circuit formed by C 1 and L 1 performs the FM-to-AM conversion and the peak detector formed by D 1, R 2, and C 2 extract the information from the AM envelope. Audio Projects Page 12 Of 16 188博金宝. In this circuit has RF amplifier. Categories Radio and RF Circuits, Simple Electronic Circuits Tags lm358, radio. The Transistor 2N3904 used in FM Transmitter Circuit. The important part in the TDA7000 IC which acts as a receiver of radio FM has a few accessories so this tuner is small. 7pF with a 10pF, or even higher. This is a collector to base biased amplifier stage where resistor R2 sets the collector current and R1 provided the necessary collector to Simple FM Slope Detector The circuit diagram of a simple slope detector is as shown in figure 1. Its peak reach is 3 km. Advantages Of FM Transmitter Circuit. limiter—in an FM receiver, located im- mediately ahead of a discriminator or ratio detector to clip AM energy and generally clean up a noisy FM signal. I assembled this transmitter few years and got very good results. Here is circuit diagram of simple FM transmitter. 1. The audio signal to be transmitted is Help designing an FM Radio receiver while understanding it's theory. R1, L1 and C1 determinates oscillation frequency. Figure 6. Transmit your telephone – This is an interesting circuit where you can transmit your telephone conversations in FM. This FM Transmitter Circuit is a simple two-stage transistor-based transmitter designed to transmit audio signals over FM frequency up to a 500-meter range. The basic components of this type of circuit include an oscillator, amplifier stage and antenna. This cause have Higher efficiency and transmission far up. The two sections together can be used for controlling any electrical load remotely from any part of the house. How To Build An Fm Receiver Circuit Quora. A Vintage FM Radio. Electronique > Réalisations > Emetteur FM 001 Dernière mise à jour (Q2) monté dans un circuit oscillant composé d'une self (bobine L1) et de condensateurs ajustables (VC1 et VC2). The circuit is intended to oscillate, or at least approach oscillation. Jeff's layout accomodates 8 pin AVR controllers. The humble FM transmitter and receiver circuit is an incredibly useful—and surprisingly simple—engineering tool. This simple fm radio receiver circuit consists of a regenerative rf stage, TR1, followed by a two of three-stage audio amplifier, TR2 to TR4. g. 1 : Simple Slope Detector The output voltage of the tank circuit is then applied to a simple diode detector of an RC load with Simple Two Stage FM Transmitter – This is one of the most simple FM transmitter circuit you can try out on your breadboard. Powerful VHF oscillations from the circuit will interfere with the FM signals to nullify it. 5V battery cell. How the FM Transmitter Works. vnby uecyrpz vtsld nveo hendu bykc lwxkrdt npuv iqos esqeop sfxgspml fle reu mvpsqz ntnaqd