Ramsey Electronics CT255 manual Some random parts, and what they do

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You may notice though that the smallest step in this case is 1/256. This 8 bit DSP is unable to accurately represent this number smaller than 3.906E-3. Most fixed points DSPs however are 16 bit, 24 and 32 bits. 24 bits of resolution means the smallest number we can represent becomes 1/(2^24) which is 5.96E-8, which is considerably smaller and more accurate. Still the math isn’t perfect, and these “steps” will accumulate over time and cause errors. A 24 bit DSP number is usually in a 0.24 fixed point binary value, 0 bits to the left, 24 to the right of the decimal point.

Some random parts, and what they do

C5 has been added to the output of the ladder to “smooth” the steps slightly. U2, the 74HC393, is so fast at its job that when an output switches it causes a slight bit of overshoot. The overshoot turned out to be about the same voltage as a half of a degree reading, causing the reading to be incorrect sometimes. This capacitor fixed that. Imagine sanding the top corners of all of your stairs in a new staircase to smooth the freshly sawed edges. It looks similar to sanded steps on an oscilloscope.

D10 is a rectifier diode. This diode converts our AC adapter input to DC, but only in what is called a half-wave rectifier. This means that only 1/2 of a complete AC cycle is used for powering the CT255. The CT255 does not require much power so a full-wave bridge circuit was not necessary. A full wave rectifier uses both halves of the AC cycle (negative and positive) for powering the circuit.

C8 helps to average the pulses that the 1/2 rectifier creates allowing the 5 volt regulator VR1 to work properly. VR1 smoothes out our incoming supply power so that it is flat instead of looking like an ocean in a storm. C7 helps the regulator VR1 work a little better, so it is included.

J1 allows you to whip up a cable with three wires and make an external sensor. When your external sensor is plugged in, it disables the internal sensor.

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Contents Computemp 255 Binary Thermometer KIT Ramsey Transmitter Kits KIT Assembly CB B OA RD in CA SE IntroductionCircuit Description Binary counterDAC Digital to Analog Converter ADC Analog to Digital Converter? In a sense…Scaling to Celsius More on the ADC Oh that extra countHow the counter oscillator works Restarting the conversion cycleFor the complicated Fahrenheit design CT255 Binary math Bit # Value 128 Some random parts, and what they do CT255 Schematic Diagram CT255 Parts Layout Diagram Parts Supplied with Your CT255 KIT CapacitorsResistors SemiconductorsRamsey LEARN-AS-YOU-BUILD KIT Assembly Enough of that ... let’s get startedCT255 Thermometer Assembly Instructions CT255 CT255 CT255 Front View LM35DZ Assembly Instructions for Custom Case CongratulationsUSE of Your Computemp Troubleshooting Guide Still Having TROUBLE?Conclusion Ramsey Kit Warranty Required Tools Additional Suggested ItemsRamsey ELECTRONICS, INC Fishers Station Drive Victor, New York Phone 585

CT255 specifications

The Ramsey Electronics CT255 is a versatile and advanced communication tool designed for radio enthusiasts and professionals alike. As a 2-meter FM transceiver, it is known for its robust performance and extensive feature set, making it ideal for both casual users and serious operators.

One of the standout features of the CT255 is its compact design, allowing for easy integration into various environments such as home stations or portable setups. The unit is built with user-friendliness in mind, featuring an intuitive interface with a clear display and easily accessible controls. This ensures that users can quickly tune into their desired frequencies and modify settings without extensive technical knowledge.

The CT255 operates on a frequency range from 144 to 148 MHz, providing access to the popular 2-meter amateur radio band. This frequency capability is complemented by an impressive output power of up to 25 watts, ensuring robust communication over extended distances. It also includes a built-in automatic repeater shift, which simplifies contacts through repeaters, making it an excellent choice for those looking to enhance their communication range.

In terms of technology, the CT255 employs advanced digital signal processing (DSP), which significantly improves audio clarity and reduces background noise. This makes communication clearer, even in less-than-ideal conditions. Additionally, the transceiver features an array of scanning functions, including memory scan and priority scan, allowing users to monitor multiple channels effortlessly.

The CT255 comes equipped with multiple memory channels, enabling easy access to frequently used frequencies. This feature is particularly useful for users who participate in various nets or have multiple repeaters they commonly contact. Moreover, the unit supports CTCSS and DCS tones, which adds an extra layer of privacy and reduces interference from unwanted transmissions.

Safety and durability are also key characteristics of the CT255. The robust construction ensures it can withstand the rigors of regular use, making it suitable for field operations. It is designed with heat dissipation features to prevent overheating during prolonged use, ensuring reliability during critical communications.

In conclusion, the Ramsey Electronics CT255 is a well-rounded transceiver that brings together advanced technology, user-centric design, and excellent performance. Its range of features makes it an appealing choice for radio amateurs seeking a dependable and efficient communication solution. Whether for casual chatting or emergency communications, the CT255 stands out as a reliable tool that meets the demands of modern radio users.
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