CIRCUIT DESCRIPTION

Let’s take a look at the schematic diagram, we will follow through from input to output to get a general idea how this kit works, and why. We will look mainly at the left channel circuitry starting at J1. Items in parentheses , ‘(xx)’, refer to the right channel signal path. Standard configuration settings will be assumed. See the optional configurations section for additional operation information.

The nitty-gritty of it all

A line level audio signal is connected to J1. Line level means an audio signal of around 1V peak to peak, will give a reading of 0dB on a VU meter. The audio passes through C9 (C10), a coupling capacitor. This capacitor prevents DC from entering the circuit from external components and interfering with audio quality. The capacitor lets the audio pass through to pin 19(2) of U3, an LM1036, which is the tone/volume/balance control IC.

This IC can be thought of as the heart of the SHA2. It provides control of all the major functions of the unit including volume, tone, balance and loudness. Without this IC there would be a large quantity of resistors, capacitors and amplifiers required to achieve the same functionality it provides. By the way, remember that it is actually two sets of these controls since this is a stereo system. R9, R10, R11 and R12 are the volume, tone and balance controls. These functions are controlled by U3 with a DC voltage applied to the respective control pins. This voltage is supplied by a built in reference source on pin 17 and each control varies the voltage on the control pins which is applied to its control pin. The loudness control, S1A, is used to provide a slight amount of bass boost when the volume is set to lower settings. Because your ear is less sensitive to low tones at low levels this provides a more robust sound at these levels. Capacitors C15 and C21 determine the way the treble control operates. Capacitors C19, and C20 are for the bass control while C16 and C18 are used both treble and bass.

After being processed the signal is sent from U3 pin 8(13) to the input of the output amplifier, U2(U4) pin 3 through C10(C17), another coupling capacitor like C9. U2(U4) is a fully integrated audio amplifier, capable of driving low impedance loads. It requires very few external components, runs very efficiently, and has great fidelity. U2(U4) amplifies the signal to drive a low impedance speaker like those in your headphones.

R7(R14) and C14(C27) on the output side of the LM386, U2(U4) is for preventing oscillations due to the inductive nature of a speaker coil being driven by the LM386. This makes the load of the speaker look more resistive rather than inductive which prevents “motorboating” of the audio signal.

SHA2 • 4

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Ramsey Electronics SHA2 manual Circuit Description, Nitty-gritty of it all
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SHA2 specifications

Ramsey Electronics SHA2 is a state-of-the-art digital transmitter designed for a wide range of applications, including DIY projects, short-range communication, and remote sensing. This powerful device allows users to transmit audio, data, and control signals wirelessly with outstanding clarity and reliability.

One of the standout features of the SHA2 is its transmission range, which can reach up to several hundred meters depending on the environment and conditions. This capability makes it an ideal choice for various applications, from hobbyist projects to more complex commercial uses. The SHA2 operates in the 2.4 GHz ISM band, which is a widely used frequency range that provides robust performance and minimal interference from other electronic devices.

The SHA2 incorporates advanced Frequency Hopping Spread Spectrum (FHSS) technology, enhancing its resilience against potential disruptions. By rapidly changing frequencies during transmission, FHSS minimizes the chance of interference and improves the overall signal integrity, ensuring a stable connection even in crowded environments. This feature is particularly beneficial for applications that require reliable and consistent data transmission.

Moreover, the SHA2 is equipped with powerful modulation schemes that support various encoding methods. As a result, users can transmit different types of signals, including analog audio, digital data, and even coded control signals. This versatility allows for creative approaches to problem-solving in diverse fields, such as automation, security systems, and wireless audio transmission.

In terms of user-friendly design, Ramsey Electronics has made the SHA2 easy to integrate into existing systems. Its compact size, along with clearly marked connection points, allows for streamlined installation. The module's low power consumption is another critical advantage, making it suitable for battery-operated devices and applications that prioritize energy efficiency.

The SHA2 is also compatible with various microcontrollers and development platforms, ensuring seamless connectivity regardless of the user's preferred technology. With its durable construction and excellent performance specifications, the Ramsey Electronics SHA2 stands out as a reliable choice for anyone looking to leverage wireless communication technology effectively. In summary, the SHA2 excels in transmission range, interference resistance, versatile signal encoding, user-friendly integration, and energy efficiency, making it a prime candidate for both hobbyists and professionals alike.
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