Stepped attenuator resistor string calculator neville roberts. Our fixed rf attenuator pe700510 is shipped sameday as purchased from pasternacks iso 9001. For the sky12347362lf, bit number 1 has the lsb value of 0. This 10db attenuator is an inline, resistive pi attenuator pad design. Therefore, using 6 ohms as the tweeters impedance, for a 1db attenuation you need a series resistor of 0. In todays world there are still many impedances used, 50 ohms for most industrial or mobile rf, 75 for most tv video and rf, 100 for lan, 600 for most balanced audio, etc. A pipad attenuator circuit is required to reduce the level of an audio signal by 10db while matching the impedance of a 75. The inverting circuit of figure 2 can be used as an attenuator by making rg larger than rf.
Pdf attenuators using thin film resistors for rf application. The smartphoneenabled dmm of course, external attenuator resistors can affect the ac curacy of the system. Hificollective hificollective 10k shunt network 46step 20k shunt network 46step input resistor. A 3 db pad reduces power to one half, 6 db to one fourth, 10 db to one tenth. Resistance value of pi and ttype attenuator pads wenteq. The left table depicts several pa db values versus ri ro 50 ohm. In a shunt type stepped attenuator, a voltage divider is formed with one constant value inputtooutput resistor, and one other resistor selected by the rotary switch position. Attenuation from 0 db to 10 db in 1 db increments, 16 db a1206, a1612, 20 db a1612 vswr 1.
Our microwave attenuator is rated to 2 watts at the stated attenuation value. It provides an at a glance view of the resistor values needed for pi, t and bridged t resistive attenuator pads, enabling an easy selection of the values as well as the most appropriate type of pad according the resistor values. Attenuator resistor values table electronics notes. Pdf this paper presents a simple methodology for deducing the resistors of attenuators.
A 10 db attenuator will have a 20 db return loss the signal is attenuated 10db going from the tx to the load, and then the reflected wave, now 10db or 10% of the transmitter power will be. Transfer the resistor values in that line to the resistors on the schematic diagram in figure above. Since all the resistors are connected to the ends or to ground, we know the voltage across each resistor, and power is just power v2 r. Hendricks 41db step rf attenuator first, familiarize yourself with the parts and check for all the components. Design me a 10 db xlr attenuator i need 10db of attenuation for a k6 me66 mic going into a sony z1 as i have heard that the k6 has dangerously high output. This can be built into a flexibox and a transmission line 50 ohm track pcb is available which easily adapts for this circuit with one simple trimming operation. Having to construct attenuators for a lan problem see a real lan twist cable it was noticed that most attenuator tables are designed around 50 ohms. I rounded off the calculated resistance values for convenience. Variable and switched attenuators are basically adjustable resistor networks that show a calibrated increase in attenuation for each switched step, for example steps of 2db or. The pi attenuator consists of one series resistor and two parallel shunt resistors to ground at the input and the output. Alternatively, generate r1 and r2 for a wanted attenuation.
What resistor values would be required for both the. The completed unit contains single 1, 2, 3 and 5 db sections, and six 10 db sections. Pa1b power attenuator calculator including download. Transfer the resistor values in that line to the resistors on the schematic diagram in the figure above. The pi attenuator consists of one series resistor and two. There is also a selection of suitable connectors available. The pasternack pe700510 10 db attenuator is rated for up to 18 ghz. Basic rf technic and laboratory manual attenuators. Dec 31, 2009 using a attenuator to protect a transmitter from high vswr, or low return loss, the return loss will improve by 2 times the value in db of the attenuator. Some variation is normal as the resistors are 5% tolerance but the values should be close unless a resistor was accidentally swapped. Calculates the resistor values, attenuation, minimum attenuation, impedance, reflection coefficient, vswr and return loss of a matching pi attenuator. Attenuators weaken or attenuate the high level output of a signal. Using a attenuator to protect a transmitter from high vswr, or low return loss, the return loss will improve by 2 times the value in db of the attenuator. The harrison labs attenuators use resistor values that are far lower than the values used in the rothwells, and consequently they will present too heavy a load to be optimal for many components which may be used to drive them.
Since an attenuator circuit consists solely of passive resistor elements, it is both. The icom r70 and r71a have a front panel switch that allows selection of either a preamplifier, a single attenuator of about 20 db, or neither. The table in the figure below lists resistor values for the l attenuators to match a 50. The enclosure is made of brass sheet stock, readily available at many hardware stores. Enter 10 followed by tab for an attenuation of 10 db. This sma attenuator has a male gender on side 1 and a sma female connector on side 2. These single bit attenuator networks consist of phemt fet switched resistor circuits in pi or. Analyzer pna e8357a produced these values shown at 7030 khz. The calculator first calculates the power that is dissipated in each of the 3 compound. Pi attenuator calculator enter values for r1 and r2 to calculate attenuator loss and impedance. For 30 db attenuators is difficult to implement for wide bandwidth, cascade attenuators can solve the problem. Table 2 lists the resistor values required for each section. Programmable attenuator the programmable attenuator, also known as a digital step attenuator, is a component controlled by an external voltage. The 10 db corresponds to a voltage attenuation ratio of k3.
Pe7005 10 is a fixed 10 db attenuator from pasternack. Mar 06, 2019 some variation is normal as the resistors are 5% tolerance but the values should be close unless a resistor was accidentally swapped. Since the op amp input is high impedance, the attenuation is set by the resistor divider. E12series the pa1b power attenuator calculator enables you to take good available resistors with a modest power, from the e12series. One of the earliest was published by the nab in 1960 for losses ranging from 12 to 40 db, for use in 600 ohm circuits.
Attenuators amplifiers and active devices electronics. Our coaxial 50 ohm attenuator is manufactured to precise rf microwave industry specifications. To assist in the design, a behavioral model is created using genesys1 linear simulation software. The simulation results shows the attenuation of stfr attenuator is 20. They are often controlled by transistortransistor logic ttl inputs, and the step sizes are typically 1, 2, 4, 8, 16, and 32. Matching pi attenuator calculator calculates the resistor values, attenuation, minimum attenuation, impedance, reflection coefficient, vswr and return loss of a matching pi attenuator. Calculates the resistor values, attenuation, impedance, reflection coefficient, vswr and return loss of a t attenuator. Yats are available with nominal attenuation values of 0 to 10 db in 1 db steps, and 12, 15, 20, and 30 db. Lessons in electric circuits volume iii semiconductors.
Perhaps the most common use of an attenuator is in 50 ohm radio circuits. Resistors r0 have maximum power dissipation at maximum attenuation in the limit as a. Stepped attenuator resistor string calculator neville. The table below provides a summary at 1 db intervals for pi section, t section and bridged t resistive attenuators for. In todays world there are still many impedances used, 50 ohms for most industrial or mobile rf, 75 for most tv video and rf, 100 for lan, 600 for most balanced. The values given in the table above for the resistive attenuator resistor values provides an easy lookup table. Resistor string value calculator for constructing stepped attenuators. The input resistor, r 1, will set the ac input resistance and also will be a contributor to the final noise of the circuit. Our pi attenuator calculator is designed to aid you in calculating the correct values of the resistors r1 and r2, according to the diagram below. An attenuator is an electronic device that reduces the power of a signal without appreciably. If we examine a pi attenuator, figure 1, we can readily determine the voltage at each end from the attenuation. Variable and switched attenuators are basically adjustable resistor networks that show a calibrated increase in attenuation for each switched step, for example steps of 2db or 6db per switch position. Mmic processing including thin film resistors on silicon substrates.
Each section consists of a dpdt slide switch and three 14w, 1%tolerance metalfilm resistors whose values are chosen to obtain the desired amount of attenuation. Note that rx and ry are made up by the string of resistors in the chain. Visit pasternacks rf coaxial attenuators page for product details. The completed unit contains single 1, 2, 3 and 5db sections, and six 10db sections. To this end i have included a small table in figure 2 below which depicts common power reduction values of 3 db, 6 db, 10 db and 20 db. Manual switches pin diode switches surface mount switches waveguide electromechanical relay switches waveguide. Simply insert the attenuator between your antenna and radio and select a value of attenuation that puts the smeter needle into the active region, then continue ri 1 61.
Less resistor gtt4 ss heavy duty zinc body st1 tool for ss sleeves ss1s abs body sss threaded front specifications fam famhr famp famphr frequency range 5 mhz 3 ghz 5 mhz 3 ghz dc 3 ghz dc 3 ghz attenuator values 3, 6, 8, 10, 12, 16, 20 db 3, 6, 8, 10, 12, 16, 20 db 3, 6, 10, 12, 20 db 3, 6, 10 db accuracy. Design an attenuator 5db, 8db, 10db or 15db, assume t type atten uator. The pi attenuator pi pad is a specific type of attenuator circuit which resembles the shape of the greek letter. A 10 db attenuator will have a 20 db return loss the signal is attenuated 10db going from the tx to the load, and then the reflected wave, now 10db or 10 % of the transmitter power will be. The required resistor values for an 18 db pi attenuator are calculated to be.