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TV Video Modulator With LM2889
2008-04-14 08:39:00
The LM2889 is designed to interface audio and video signals to the antenna terminals of a TV receiver. It consists of a sound subcarrier oscillator and FM modulator, video clamp, and RF oscillators and modulators for two low-VHF channels.The LM2889 allows video information from VTRs, video disk systems, games, test equipment, or similar sources to be displayed on black and white or color TV receivers.Features:* Pin for pin compatible with LM1889 RF section* Low distortion FM sound modulator (less than 1% THD)* Video clamp for AC-coupled video* Low sound oscillator harmonic levels* 10V to 16V supply operation* DC channel switching* Excellent oscillator stability* Low intermodulation productsDownload datasheet - Application Note For Stereo Audio

Video Modulator With PLL Output
2008-04-14 08:32:00
Circuit DescriptionOscillatorThe RF-oscillator is available at pins 3-7. The oscillator operates as a symmetrical Colpitts circuit. The oscillator chip ground, pin 5, should be connected to ground at the resonance circuit shielding point. An external oscillator can be injected inductively or capacitively via pins 3 and 7. The layout of the PCB should be such as to provide a minimum shielding attenuation between the oscillator pins 3-7 and modulator output pins 15-17 of approximately 80 dB.For optimal residual carrier suppression, the symmetrical mixer outputs at pins 15, 17 should be connected to a matched balanced-to-unbalanced broadband transformer, e.g. a Guanella transformer with good phase precision at 0o and 180o. The transmission loss should be less than 3 dB. In addition, an LC-low pass filter combination is required at the output. The cut-off frequency of the low pass filter combination must exceed the maximum operating frequency.Video The video signal with the negative sync...

RF Power Meter 0-500MHz With PIC16F876
2008-04-14 08:27:00
RF Measurement has been an expensive work so far the cost of measuring instruments are concerned. RF Meter is based on PIC16F876 microcontroller, AD8307 and 2x20 LCD display. Frequency range measurement is 0-500 MHz and Full documentation is included.This power meter kit has two push buttons to control the functions. Very cost effective and simple to use. 4 Push buttons used in this kit are right angle type and are sufficiently long enough to come out of the box, if you decide to house this meter in a case.Download Project Domumentation, Schematic, Hex Code, and Visit page
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PLL TV RF Modulator CXA1929
2008-04-06 14:17:00
Fully synthesized I2C controlled UHF/VHF TV RF Modulator compatible with PAL and NTSC video formats.Features? Minimal adjustment of external components? For use on VHF and UHF TV Frequencies? Video RF carrier frequency programmable in 125kHz steps? ATT Driver? I2C control of:a. Video RF Carrier Frequencyb. Sound Carrier Frequencyc. Modulation Depth (±2.5 % Typ.)d. FM Deviation (±7 % Typ.)e. P/S ratio (±1 dB Typ.)f. Nicam output enable to sleepg. Video RF carrier enable to sleep? On chip Regulator 3.1 V (datasheet)Functional Description of RF Modulator SystemA block diagram of the RF modulator is shown in datasheet The composite video signal passes through an amplitude limiting circuit and a digitally controlled modulation depth adjustment circuit. By means of three allocated I2C control bits it is possible to adjust the modulationdepth from a nominal 74 % to 86% in 2.0 % steps. Modulation depth can also be controlled externally byaddition of an external resistor on pin3. The video s...

CATV amplifier module BGX881
2008-03-30 17:55:00
DescriptionThis CATV amplifier module is a product of Philips Semiconductor, hybrid amplifier module CATV systems operating over frequency range of 40-860 MHz at a voltage supply of 24V DC with features :· Excellent linearity· Extremely low noise· Silicon nitride passivation· Rugged construction· Gold metallization ensures excellent reliability.This CATV Module can be used to amplify your CATV Modulator for 13 dB. And in my technical experiences in tv transmitter it can not only used on cable media, but also it can be used on air via a suitable antenna. With Adding a TV low pass filter you are able to transmit your video for 1 km.CircuitComponentsC1, C3, C4 ceramic multilayer capacitor 1nFC2 ceramic multilayer capacitor 1nF(max)R resistor 200 Ohm 1WPins 1 and 9 carry DC Voltages
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AV Modulator for UHF Band NJM2259
2008-03-30 16:55:00
The NJM2259 is a RF modulator IC especially designed for UHF band RF modulator and consists of video clamp circuit, white clip circuit, video AM modulator and audio FM modulator, built into one chip. (datasheet)FEATURES :? Operating Voltage 5V? Picture-to-sound ratio is adjustable? Audio ripple is decreased by two internal regulators? Audio input circuit with low shock noise? Carrier-off switch function on chip? Bipolar Technology? Package Outline : DMP16
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Horizontal Polarized UHF Panel TV Antenna
2008-03-27 11:46:00
This UHF Panel Antenna designed for broadband TV Transmission Antenna in UHF Band IV and V. For broadband use, try to design adapter 50 Ohm to 260-300 Ohm for mid band frequency of 470-860 MHz. With 50 Ohm Antenna Impedance input that composed from dual single antenna, you need two lines transmssion adapter (Antenna Power Divider) for combining. Combining two single antenna in order to increase antenna intensity (dB)If you want to constuct this panel antenna type, use this reference on images below:Stacking more panels it's possible to obtain customized patterns, increse the gain and the power handling capacity according to your requirements. Datasheet reference.

14 Watts UHF TV RF Amplifier #2
2008-03-22 23:30:00
From #1 UHF TV RF amplifierBIAS CIRCUITComponent Part List:C1, C2, C4, C5, C6 = 1nF LCC Chip + 10nF LCC ChipC3 = 100µF SpragueC7 = 10µF SpragueD1 = 1N 4001L1, L2 = 5 Turns , Diameter 0.5 mm, W Diameter 3mmP1 = 1k.R1 = 56 ohm/ 1/2WR2 = 5600 ohm, 1/2WR3 = 2.2 ohm, 3WR4, R5 = 56 ohm, 1WR6 = 4,7 ohm, 1/2WT1 : BDX 54 B/BD139Previous Page ...
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Microwave Power Meter #2
2008-03-22 23:22:00
Some remarksThe input circuit determines the frequency characteristics of the meter. When using Schottky diodes like 1SS99 or HP5082/2800 and a 'microwave' design of the input circuit (C_in: use a smd type, 50 ohm terminator: use 2 smd resistors of 100 Ohm), proper earth etc, a reasonably flat frequency characteristic up to 1.5 GHz is easy to obtain. When the input C (C_in) is reduced to about 20 pF, and BAT14 diodes are used as the detector, proper measurements up to 3.5 GHz (+/- 1 dB) can be obtained. In this case the meter will also detect 10 GHz signals, but the frequency characteristic (above 3.5 GHz) of the input circuit is far from flat, so no real power measurement can be done on these frequencies. As an experiment C_in was reduced to 0.68 pF and the diodes used are BAT14. Power can now be detected over a very large (up to 26 GHz) frequency range; as the frequency characteristic is far from flat, a calibration in mW / uW is not useful.Practical experienceThe electronic cir...
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Wideband Amplifer 470-860 MHz For TV Transmitter #2
2008-03-22 23:07:00
MECHANICAL MACHINING OF THE HEATSINKThe raised edges at the top side of the heatsink have been removed because the printed circuit board has a width of 113 mm (see Fig.3). To fit the heatsink to the printed-circuit board the following machinings have been carried out:Rectangular holes of 2.8 mm deep have been mould in the heatsink because the transistor leads have to be soldered on the printed-circuit board. Also it was necessary to make avings of 4 mm wide and 0.6 mm deep at the positions of the straps on the printed-circuit board. The transistors have been fastened with M 2.5 screws in the heatsink (see Fig.4). To achieve that the printed-circuit board lays tight to the heatsink also savings have been made in the heatsink on the spots of the 8 rivets through the printed-circuit board. For fastening the printed-circuit board on the heatsink on 7 places, holes with M 3 screwthread have been made in the top side of the heatsink, corresponding with indicated holes in the printed-circu...
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Microwave Homemade Outdoor Antenna 2.4 GHz #2
2008-03-22 22:53:00
If the inner wire is made from rod it is good idea to drill axially a 3 mm hole on the end of it so the rod can be solder firmly to the inner tap of the N connector. The length of the rod becomes about L/4, but it is better first to leave it longer and cut it later after the parts are first pre-assembled.The copper conduit must be split with a metal saw as accurately as possible and deburred with a file. The end of the split conduit is then fastened to the centre of the pan. It is not possible to solder it directly to aluminium but we made a flange from tinned steel sheet to same dimensions as the flange of the N connector. In the middle of the flange is drilled a hole equal the outer dia of the conduit and four 3.5 mm holes as in the N connector. The one end of the split conduit is then soldered in the centre hole of the flange while keeping the width of the slots between halves to 1-1.5 mm.The split conduit is then cut so that the length of the open slots becomes a very accurate L...
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Privacy Policy for broadcasthardware.blogspot.com
2008-03-19 02:55:00
Privacy Policy for broadcasthardware.blogspot.comIf you require any more information or have any questions about our privacy policy, please feel free to contact us by email at bhard@telkom.net.At broadcasthardware.blogspot.com, the privacy of our visitors is of extreme importance to us. This privacy policy document outlines the types of personal information is received and collected by broadcasthardware.blogspot.com and how it is used.Log FilesLike many other Web sites, broadcasthardware.blogspot.com makes use of log files. The information inside the log files includes internet protocol ( IP ) addresses, type of browser, Internet Service Provider ( ISP ), date/time stamp, referring/exit pages, and number of clicks to analyze trends, administer the site, track user?s movement around the site, and gather demographic information. IP addresses, and other such information are not linked to any information that is personally identifiable.Cookies and Web Beaconsbroadcasthardware.blogspot.c...
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Understanding TV Modulators
2008-03-13 20:24:00
INTRODUCTIONThe Modulator is an indispensable part of any Headend or control room. Most CATV technicians accept the use of Modulators and the fact that each channel requires a Modulator at the Headend. However often, details of why modulation is necessary to beginwith or the differences between various Modulators topology such as Saw Filter, single PLL, Double PLL and Frequency Agile Modulators, is often not fully understood. This article sets out to address these matters, in simple, easy to understand language.MODULATIONWhile we all understand that a Modulator is required to modulate each channel at the CATV Headend, why do we need tomodulate ? If we were to pass a single RF signal on a Cable TV network, the coaxial cable is well suited for the application. However, even one channel actually consists of two signals, in its simplest form the audio signal and the video signal. Therefore we would actually require two cables to carry a single television channel ! The situation would b...
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TV Modulator Circuit
2008-03-13 16:54:00
The MC1374 includes an FM audio modulator, sound carrier oscillator, RF oscillator, and RF dual input modulator. It is designed to generate a TV signal from audio and video inputs. This TV modulator based MC1374 IC From Motorola with wide dynamic range and low distortion audio make it particularly well suited for applications such as video tape recorders, video disc players, TV games and subscription decoders.The IC features:Single Supply, 5.0 V to 12 VChannel 3 or 4 OperationVariable Gain RF ModulatorWide Dynamic RangeLow Intermodulation DistortionPositive or Negative SyncLow Audio DistortionFew External ComponentsFor more info download datasheet - application note
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1W Linear Power Amplifier 2.4 GHz
2008-03-12 22:54:00
The following single-stage transistor linear amplifier possesses a gain of approximately 7 dB and an output power of 1 W in the 13 cm band (approx. 2.4 GHz). It is thus suitable for use, for instance, together with the 13 cm transmit converter. This hybrid power mixer equipped with a varactor diode type BXY. This mean that the described power amplifier can provide linear output power in the order of 1 W.CIRCUIT DESCRIPTIONA transistor type F1E6 manufactured by CTC is used. In this case of this transistor, the emitter is internally connected to the cooling bolt. This ensures that there are no problems with respect to the high-frequency grounding of the emitter. The circuit diagram of this amplifier is given in figure 1. The matching of the transistor input and ouput impedance to 50 Ohm is made using standard method in (2) The circuit for adjusting and stabilizing the DC-operating point is similar to the method described in (3)CONSTRUCTIONDouble coated, epoxy glassfibre material is...
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UHF VHF PLL TV EXCITER MC44BS374TI
2008-03-09 10:26:00
This UHF VHF PLL TV TRANSMITTER use a MC44BS374TI from Freescale. MC44BS374 is audio and video modulator for use in Transmit Video and audio and similar device. These IC are the next generation of the MC44BC374TI with the following new features :- TV output level 83dBuV- 5V and 3.3V compatible I2C bus- Logic Output Port pin (pin 3) availableMC44BS374 IS a PAL/NTSC Modulator with Integrated VCOThe channel is set by an on-chip high-speed I2C compatible bus receiver. A Phase-Locked Loop (PLL)tunes the modulator over the full UHF range.The modulator incorporates a sound subcarrier oscillator and uses a second PLL to derive 4.5, 5.5, 6.0,and 6.5 MHz subcarrier frequencies. These frequencies are selectable by bus.The picture-to-sound ratio may be adjusted using the bus. In addition, an on-chip video test pattern generator can be switched ON with a 1 KHz audio test signal.SCHEMATIC DESCRIPTIONDownload Schematic in PDF format, Trial HEX CODEA MC44BS374 R.F Modulator I.C is used to provide t...

BH1415F FM Stereo PLL Transmitter
2008-03-09 09:19:00
This is FM PLL Stereo based BH1415F IC from Rohm, it's has built in PLL and Stereo Encoder. You can download the schematic, pcb layout and Hex code. The transmitter menu display with LCD, and this have step 100Khz, 200Khz,.....1000Khz and have Mode menu (stereo/mono). In Action, LCD Display can solder directly on the bottom.Download : schematic, PCB all layer, top layer, bottom layer, hex codeBuy all components for this application here
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3 W Broadband Amplifier For UHF TV Transposers
2008-03-07 18:03:00
A broadband linear amplifier design is presented, suitable for application in TV transposers, operating in band IV and V(470 - 860) MHz. The design is based on a BLW898 bipolar transistor. Typical results at the recommended class-A biaspoint (25 V/1.1 A) for the total module include a 3-tone IMD level of -64 dB (fvision = -8 dB, fsideband = -16 dB and fsound = -10 dB) and an average gain of 10.5 dB at 3 W peak-sync output power in the (470 - 860) MHz frequencyrange.The BLW898 is a bipolar linear power transistor designed to operate in the (470 - 860) MHz range. The transistor isencapsulated in a SOT171A 6-lead rectangular flange package with a ceramic cap. The specified output power is 3 W peak-sync in class-A. The intermodulation distortion level (IMD) 10 dB at 860 MHz.For application in TV transposers for Band IV/V (470 - 860) MHz a wideband linear power amplifier has been designedoperating in class-A. It is suitable for driving higher power stages in TV-transposers. (datasheet)
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Microwave Homemade Outdoor Antenna 2.4 GHz
2008-03-06 04:57:00
DimensioningThe very first point in antenna dimensioning is to calculate the wavelength (the Lambda character has been replaced with letter L ):L /mm = 300 / (f/GHz) at 2.45 GHz L = 122 mm.Antenna picture without mast fasteners: Main parts can been found even in mama's dish cabinet but maybe safer to buy them from a department store. The Reflector is made from an aluminium cake pan and the Cover from a plastic microwave bulb, both 240--250 mm dia. The pan must be straight and smooth without profilations and the sides will be orthogonal with the bottom. If you find a pan made from stainless steel may be that may be better. I used a pan from italo ottinetti code 140024 , whose sides were 60 mm and I cut them to 32 mm.Other parts needed:A piece of copper water conduit, internal dia 10 mm, length below 40 mmA piece of brass rod, outer dia 4-4.5 mm, length N-connector, panel socketA couple pieces of tinned steel sheet e.g. from tin canA piece of PVC coated electric wire 1,5 mm2Scre...
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BLV859 UHF Linear Push Pull Power Amplifier
2008-02-18 15:38:00
A broadband linear amplifier design is presented, suitable for application in TV transposers operating in band IV and V (470 to 860 MHz). The design is based on two BLV859 bipolar transistorscombined with quadrature hybrids. Typical results at the recommended class-A bias point (25.5 V/9.1 A) for the total module include 40 W peak sync output power at -54 dB three tone IMD level (fvision = -8 dB, fsound = -10 dB, fsideband = -16 dB) and an average gain of 10.5 dB in the (470 to 860) MHz range.The BLV859 is a bipolar linear push-pull power transistor designed to operate in the 460 to 860 MHz range. With a specified output power of 20 W peak-sync in class-A it is the largest device in the new generation of transposer transistors. The intermodulation distortion level is 10 dB at 860 MHz. For application in TV transposers for Band IV/V (470 to 860 MHz) a wideband linear power amplifier has been designed with two BLV859 transistors in class-A.The amplifier consists of 2 balanced circuits...
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FET Audio Limiter
2008-02-15 07:26:00
This applicationis a very high specification peak control limiter. It has fast become the essential deviation limiter for FM radioThe application divided into two parts :Broadband Limiter Splitband LimiterActive component : FET 2N5457 and Ics NE5534, 2N5532, TL071 TL072.Download schematic and component mounted in Coreldraw 12 Format.
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Wideband Amplifer 470-860 MHz For TV Transmitter
2008-02-09 16:26:00
INTRODUCTION The construction taken from the application report NCO8101 two amplifiers for band 4/5 with BLV57 transistors have been described. Reactions on this report proved the necessity to give more information about the construction of these amplifiers. This construction has been based on a heatsink with a printed-circuit board at the upper side and the bias circuits and a forced air-cooling at the lower side. (download datasheet for schematic and instruction)PRINTED CIRCUIT BOARD In the printed-circuit board rectangular holes have been made to mount the BLV57 transistors on the heatsink. For fastening of the printed-circuit board on the heatsink by means of screws, 7 holes of 3.1 mm Æ and for fastening of the hybrid couplers 8 holes of 2.6 mm Æ have been made on the indicated places (see Figs 1 and 2). Hereby has been taken into account the use of Anaren hybrid couplers, type 10264 - 3, suited for the frequency range of 500 - 1000 MHz. Because the 2 bias units have been situat...
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100 Watts UHF Band IV-V TV Power Amplifier
2008-02-06 05:36:00
The TV amplifier has been tuned under class-A small-signal conditions and characterised under large signal class-AB conditions from band IV - V in UHF. (All Datasheets)Amplifier Circuit The total description of the amplifier is given in Figs 6 and 7 and Table 8 (in datasheet). The amplifiers input and output matching networks contain mixed microstrip-lumped elements networks to transform the terminal impedance levels to approx. 25 W balanced. The remaining transformation to 50 W unbalanced is obtained by 1 : 2 balun transformers. The baluns B1 and B2 are 25 W semi-rigid coax cables with an electrical length of 45° at midband and a diameter of 1.8 mm, soldered over the whole length on top of microstrip lines. To keep the circuit in balance two stubs L1 and L8 with the same length have been added. For low frequency stability enhancement the input balun stubs are connected to the bias point by means of 1 W series resistors. Large capacitors (C4 and C11) are added at the biasing points ...
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Microwave Power Meter
2008-02-04 04:55:00
Article from Hans Wagemans, ON4CDU A sensitive power meter is a very useful instrument when doing experiments. A few years ago when I started my microwave radio hobby up again, the first project I undertook was building a 23 cm transverter. During the development, a diode in front of my analog meter (VOM) was used to tune the microwave circuits to the resonance frequency. During the experiments, the need for a more sensitive and precise power meter was recognised. After some experiments it turned out that, based on the principle of the diode rectifier with a cheap amplifier behind it, a simple, but also sensitive and accurate power meter could be built. The circuitThe input circuit consists of a 'wide dynamic range' RF diode detector. This 'wide dynamic range' is obtained by applying a bias current of about 25 uA through the detector diode (D2). When using different diodes, the current can be adjusted by changing the 220 k resistors. Due to the bias current the detector has a go...
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Oxygen FM Manager
2008-01-31 12:04:00
Oxygen FM Manager is designed to give you full control over Nokia phones FM Radio. Load FM station presets from the phone to the PC's memory, easily edit them and upload back with just couple of clicks. Create custom FM presets, save them on disk and send them to the phone anytime you want. Oxygen FM Manager grants access to the Oxygen Online FM Stations Library that contains information about FM stations in cities all over the world.Compatibility :Program supports the following phones: Nokia 2255, 2300, 2355, 2855, 2855i, 3152, 3155, 3155i, 3200, 3205, 3300, 5100, 5140, 5140i, 6030, 6070, 6101, 6102, 6103, 6111, 6112, 6125, 6126, 6131, 6133, 6136, 6151, 6155, 6155i, 6165, 6165i, 6175i, 6200, 6220, 6225, 6230, 6230i, 6233, 6234, 6235, 6235i, 6236i, 6255, 6256, 6265, 6265i, 6268, 6270, 6275, 6280, 6282, 6510, 6585, 6590, 6610, 6610i, 6800, 6810, 7200, 7210, 7250, 7250i, 7260, 7270, 7280, 7360, 7370, 7380, 8310, 8800, 8801.Currently FM Manager doesn't support smartphones.License : F...
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14 Watts UHF TV RF Amplifier
2008-01-21 11:11:00
This amplifier work in frequency 470 - 860 MHz Band IV DAN V with power out 14 Watts with input power 1.5 Watts.SchematicPart Lists:C1 = C6 = C16 = 4,7 pF (500 V) multilayer ceramic chip capacitorC2 = C3 = C20 = C21 = 33 pF multilayer ceramic chip capacitorC4 = C9 = C13 = C19 = 1,2 to 3,5 pF film dielectric trimmerC5 = C7 = C15 = C17 = 100 nF multilayer ceramic chip capacitorC8 = C10 = C11 = C12 = 220 pF multilayer ceramic chip capacitorC14 = C18 = 6,8 mF/40 V solid aluminium electrolytic capacitorC22 = C23 = 1 pF (500 V) multilayer ceramic chip capacitorL1 = L2 = L13 = L14 = Coax. 50 Ohm with diameter 2,2 mm; lenght 29,0 mm, soldered on striplines75 W (1,1 mm ´ 28,0 mm). inner L1 dan L13 not connectedL3 = L4 = 52 W stripline (2,0 mm ´ 16,5 mm)L5 = L8 = 470 nH microchokeL6 = L7 = 39 W stripline (3,1 mm ´ 8,0 mm)L9 = L12 = 1 Turn (1,0 mm); diameter 5,5 mm; lead space 2 ´ 3,5 mmL10 = L11 = 39 W stripline (3,1 mm ´ 34,0 mm)L3, L4, L6, L7, L10 dan L11 are striplines on PTFE fibre-glass ...
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Simple RF Amplifier Protector Circuit
2008-01-18 11:30:00
This circuit protector is so simple, but it has big function in protecting your rf amplifier device. The input part signals for protecting are :Termo Switch (Heat Sensor Resistance) from your active component, RF Power transistor/FET.Forward and Reflect (reverse) from your directional coupler after your Low Pass Filter Output.Over Drive from directional coupler at the input of your rf amplifier to limit power input in normal condition.Relay (12v DC) for disconnecting power supply of your RF amplifier if condition for protecting happened.Attention :Do it manually before you install it in real condition. Don't forget to adjust 50K resistor for every input parts.
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CONVERT AV TO VHF TV RF Signal
2008-01-17 04:55:00
Small Circuit to send your Audio Video from DVD player or satellite receiver to VHF RF signal. This circuit connected to TV RF input via 75 ohm cable or telescopic antenna. Don?t use this circuit for more power without filter and use antenna only to transmit. Frequency range on vhf band about 50-250 MHz.You can change the transistor for transmitting on UHF band. Keep the components lead shortly. Recommended use crystal or PLL technic for stability of frequency.
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How To Stack Your Antenna On FM Broadcast Band
2008-01-14 09:33:00
Stacking your broadcast antenna will make your antenna have more gain. If your antenna have more gain, more ERP (Emmittion Radiating Power).What do you need for stacking antenna?- More antennas that identical each others.- Power divider to distribute your RF power to each antenna.- Jumper cables to connect antennasFor Stacking 4 Antenna Antenna : prepare 4 identical antenna. Tune the antenna for Matching on the working frequency.Power Divider : prepare 1 power divider with 1 port input and 4 ports output. Jumper Cables : any length of coax cable with 2 N connectors to connect between power divider and antennas.Determinate Range between Antennas ? When you install the antennas in collinear system, you must observe the distant ?D? (see drawing of follow page) between two antennas. The formula for calculate ?D? is: D = 0.75 x ? Where :0.75 = is the multiplicative coefficient;300? = -----------F(MHz)SWR reading on the frequency 94.4 Mhz
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FM LowPass Filter For 88-108 MHz
2008-01-13 10:50:00
Filter used for eliminate unwanted harmonic frequency at second and third. Notch filter, Band Pass Filter, and High Pass Filter sometime combined in constructing LPF design. Schematic below for FM Broadcast Lowpass Filter 88-108 MHz. It has tested with good result.Note : Make the coils at 74 nH and trim them to adjust exact value.
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