This website uses cookies. If you continue to browse the site, we assume you are fine with how we use cookies on the web. We're sorry but the page you are looking for does not exist. Here are some links that do, hopefully you will find what you are looking for at: Home of RF and Wireless Vendors and Resources One Stop For Your RF and Wireless Need Crowded mast with TMAs (white rectangular boxes) mounted behind all the panel (rectangular) antennas A Tower Mounted Amplifier or Mast Head Amplifier is a Low-noise amplifier (LNA) mounted as close as practical to the antenna in mobile masts or base transceiver stations. A TMA reduces the base transceiver station noise figure (NF) and therefore improves its overall sensitivity; in other words the mobile mast is able to receive weaker signals. In two way communications systems, there are occasions when one way, one link, is weaker than the other, normally referenced as unbalanced links. This can be fixed by making the transmitter on that link stronger or the receiver more sensitive to weaker signals.

TMAs are used in mobile networks to improve the sensitivity of the uplink in mobile phone masts. Since the transmitter is a mobile phone it cannot be easily modified to transmit stronger signals. Improving the uplink translates into a combination of better coverage and mobile transmitting at less power, which in turn implies a lower drain from its batteries, thus a longer battery charge. There are occasions when the cable between the antenna and the receiver is so lossy (too thin or too long) that the signal weakens from the antenna before reaching the receiver; therefore it may be decided to install TMAs from the start to make the system viable. In other words, the TMA can only partially correct, or palliate, the link imbalance. Simple phone mast with three TMAs (horizontal rectangular boxes) visible at the top of metal tower and before rectangular antennas In a receiver, the receiving path starts with the signal originating at the antenna. Then the signal is amplified in further stages within the receiver.

It is actually not amplified all at once but in stages, with some stages producing other changes (like changing the signal's frequency). The principle can be demonstrated mathematically; the receiver's noise figure is calculated by modularly assessing each amplifier stage. Each stage consists of a noise figure (F) and an amount of amplification, or gain (G). So amplifier number 1 will be right after the antenna and described by and . The relationship of the stages is known as the Friis formula. Start with a typical receiver: Antenna - Connecting Cable (stage 1) - Receiver (stage 2). The first stage after the antenna is actually the connecting cable. What can be done to improve the receiver to pick up very weak signals? It must have a lower noise figure; that is when the TMA comes into use. It is a chain of 4 modules: antenna - short connecting cable (stage 1) - TMA (stage 2) - longer connecting cable (stage 3) - receiver (stage 4) Updating the Friis formula with this case, the noise figure is now:

In this way, the cable losses are now negligible and do not significantly affect the system noise figure.quicksmart backpack stroller buy This number is normally expressed in decibels (dB) thus:backpack sakurajima ^ Noise Figure of lossy stagezephyr backpack coteSince 1885, Becker has been manufacturing and developing technologies that position Becker as the number one choice for vacuum pumps, pressure pumps, compressors, regenerative blowers and central systems.  case logic black 16 laptop backpack model dlbp-116The Becker rotary vane vacuum pump leads the industry with unparalleled technology that provides reliable, superior performance cycle after cycle.case logic black 16 laptop backpack model dlbp-116

We'll start with the top pins BAT+, GND, USB+, and 3V or 5Vskooled backpack BAT+ is the Battery + Input pin. If you want to power the Pro Trinket from a battery or power adapter or solar panel or any other kind of power source, connect the + (positive) pin here! You can connect up to 16V DC. If you have a 3V Pro Trinket, you'll want at least 3.5V input to get a good 3.3V output. If you have a 5V Pro Trinket, 5.5V or higher is suggested. This input is reverse-polarity protected. GND is the common ground pin, used for logic and power. It is connected to the USB ground and the power regulator, etc. This is the pin you'll want to use for any and all ground connections BUS is the USB Bus + Output pin. If you want to use the USB 5V power for something, like charging a battery, or if you need more than 150mA of current (this pin can supply 500mA+ from USB ports) or to detect when the Pro Trinket is plugged into USB, this pin will have 5V power on it if and only if its plugged into something via the micro B connector.

Don't put power into this pin, that's what BAT+ is for - use it only as an output! The next pin is either 3V or 5V depending on which Trinket Pro you have. It is the output of the low dropout regulator. The regulator is powered by either BUS or BAT (whichever is higher!) It will automatically switch between the two if USB or battery is removed using two schottky diodes. There is a 0.2V dropout due to the diode and maybe 50-100mV minimum drop in the regulator. The regulator can supply approximately 150mA as long as it doesnt overheat. Make sure that you keep BAT+ low to minimize heat-loss! About 1 or 2 Volts higher than 3V or 5V is ideal. Next we will cover the 18 GPIO (General Purpose Input Ouput) pins! 18 GPIO is a big step up from the little Trinket with only 5 or so pins. This is almost as many as a 'full grown' Arduino. In fact, since the Pro Trinket uses the same core chip as an Arduino, nearly any existing project that uses special pins like hardware PWM or SPI will work 'out of the box'.

All the GPIO pins can be used as digital inputs, digital outputs, for LEDs, buttons and switches etc. They can provide up to 20mA of current. Don't connect a motor or other high-power component directly to the pins! Instead, use a transistor to power the DC motor on/off On a 3V Pro Trinket, the GPIO are 3.3V output level, and should not be used with 5V inputs. On a 5V Pro Trinket, the GPIO are 5V output level, and can be used with 3V inputs but may damage electronic devices that are 3V input only! The Digital Only GPIO Pins RX - also known as Digital #0, this is the hardware serial input pin. This is used when programming with an FTDI cable but is available when using the native USB to program TX - also known as Digital #1, this is the hardware serial output pin. Digital 3 - Also known as external interrupt #1. This pin can also be used as a PWM output pin using analogWrite() Digital 4 - Nothing particularly special about this GPIO pin Digital 5 - this pin can also be used as a PWM output pin using analogWrite()

Digital 6 - this pin can also be used as a PWM output pin using analogWrite() Digital 8 - Nothing particularly special about this GPIO pin Digital 9 - this pin can also be used as a PWM output pin using analogWrite() It's also good for driving servos because its a high-speed PWM output Digital 10 - this pin can also be used as a PWM output pin using analogWrite() It's also good for driving servos because its a high-speed PWM output Digital 11 - Also known as the SPI MOSI pin. this pin can also be used as a PWM output pin using analogWrite() Digital 12 - Also known as the SPI MISO pin Digital 13 - Also known as the SPI CLOCK pin. This is also connected to the red #13 LED! The Analog/Digital GPIO Pins Analog 0 - also known as Digital 14, this pin can be a digital I/O pin or an analog input pin Analog 1 - also known as Digital 15, this pin can be a digital I/O pin or an analog input pin Analog 2 - also known as Digital 16, this pin can be a digital I/O pin or an analog input pin

Analog 3 - also known as Digital 17, this pin can be a digital I/O pin or an analog input pin Analog 4 - also known as Digital 18, this pin can be a digital I/O pin or an analog input pin. It's also the I2C SDA pin Analog 5 - also known as Digital 19, this pin can be a digital I/O pin or an analog input pin. It's also the I2C SCL pin The Analog only pins The two pins that sit sort-of inside the body of the Pro Trinket, A6 and A7, are analog input only pins. They're kind of an 'extra' that you get with the Pro Trinket. These pins cannot be used for LEDs, buttons, servos, etc. They're only for analogRead() usage! If you're used to using an Arduino Uno, you may notice that pins #2 and #7 are not available. That's because we use those two pins for the USB bootloader. They are not available for use and are not broken out. Aref - this is the optional analog reference pin for the analog converter, to be used when you want the 'top' of the analog converter to be different than 3V or 5V.