Below are frequently asked questions and answers about the GB-4000 Frequency Generator and SR-4 Amplifier.


GB-4000 Frequently asked questions and answers………


Q1: Does the GB-4000 output its frequencies digital or analog?

A: Analog.

Q2: Does the GB-4000 use crystal controlled frequencies for high accuracy.

A: Yes it does for the 3.1 MHz RF carrier frequency. The GB-4000 also goes beyond using crystal-controlled frequencies. It also uses digital frequencies output from a DSP (Digital Signal Processor).

Q3: How does the GB-4000 frequency Instrument output its frequencies analog when they come from a digital DSP chip?

A: The GB-4000 uses a DAC (Digital to Analog Converter). This type of electronic circuit is used in all modern analog frequency generators. The frequencies are output from a DSP, (Digital Signal Processor) then go through the DAC and then through a low pass or band pass filter and come out converted to analog. These frequencies are phase-locked-looped for perfect accuracy. By this method we have all the harmonic content of the old antique vacuum tube frequency generators along with the digital accuracy. No old antique frequency generator has the frequency accuracy of today’s modern equipment. This method is now the standard in the industry.

Q4: Can the GB-4000 frequency machine output RF or Radio Frequencies.

A: Yes. The GB-4000 has a frequency range from 1 to 20 million Hertz (20 Megahertz).

Q5: What is an RF Carrier Frequency?

A: Any radio station uses an RF carrier frequency to carry or modulate (piggyback) the audio frequencies, voice or music that is sent out for you to hear on your radio. Modulation is the mixing of the RF carrier frequency with the audio frequencies. So, the RF carrier frequency is the means by which the radio station transmits the signal through the air to you the listener. The GB-4000 goes beyond what most carrier frequencies are designed to do. It produces harmonic sidebands replicating the output of the 1930's, 1940's and 1950's M.O.P.A. style equipment.

Q6: Why do most frequency generator manufacturers limit their audio frequency modulation to 1000 Hertz?

A: Most likely they just did not want to spend the money to build the circuit with a higher capability. This is just one of the several differences between the GB-4000 and most of the other frequency generators on the market today. The GB4000 can modulate any frequency from 1 Hertz to 999,999 Hertz on its carrier frequency.

Q7: What is the main difference between the GB-4000 and other function generators?

A: The GB-4000 can output up to 8 audio frequencies simultaneously up to 40,000 Hertz.

Q8: What is the highest frequency that the GB-4000 can output?

A: 20 million Hertz.

Q9: Most other manufacturers only have a frequency range to 10,000 Hertz. Some go up to 22,000 Hertz. The GB-4000 goes to 20,000,000 Hertz. Why?

A. It is all a matter of what frequency range the manufacturer wants to cover. The higher the frequency range the more versatile the generator will be.

Q10: How much more powerful is the GB-4000 than other frequency generators?

A: Because of the use of an RF carrier frequency the GB-4000 is over 27 times more powerful than most other frequency generators. If the SR-4 amplifier is connected to the GB-4000 is 150 times more powerful than other frequency generators that do not use an RF carrier frequency.

Q11: Why should I want the optional Amplifier?

A: The GB-4000 can operate in two different modes. 1: RF Mode, which is the higher frequency mode, 2: Audio Mode, which is the lower frequency mode. In RF mode, the GB-4000 has an output of 5.4 watts peak power; however, sometimes more power is wanted. The SR-4 Amplifier boosts the GB-4000 5.4 watt RF output to about 30 watts of RF peak power output. Also, the Amplifier has three additional sets of outputs for more hookups. The SR-4 is 15 watts RMS or 30 watts peak power Amplifier and operates in the RF mode only.

Q12: Why was the GB-4000 built to output up to 8 frequencies simultaneously to 40,000 Hertz while most other instruments only output one frequency at a time?

A: It was designed to be a time saving feature.

Q13: Does the GB-4000 show the actual frequency being used on the LCD?

A: Yes. The GB-4000 shows the actual frequency on the LCD as long as you are not running multiple frequencies.

Q14: Some manufacturers build their instruments with built in rechargeable batteries. Why doesn't the GB-4000 have this capability?

A: The reason the GB-4000 is not battery operated is because of its power output range. Rechargeable instruments only have 28 volts peak to peak voltage output. In the audio mode the GB-4000 is variable and has a range from 0 to about 36 volts peak to peak. In the RF mode the GB-4000 is variable from 0 to over 100 volts peak to peak. Because of these capabilities it is not feasible to put batteries into the GB-4000.

Q15. Does the GB-4000 have programmable memory?

A: Yes. It has enough memory to program up to two thousand auto channels holding 48 frequencies each.

Q16: What is gating and how does it work?

A: Gating is basically an advanced "pulsing" feature. When turned on it pulses any frequency on and off at the pre-determined gate rate.

Q17: Why does the GB-4000 have a 10% to 90% duty cycle range?

A: All high quality frequency generators have this capability because different duty cycles are needed in testing.

Q18: Can the GB-4000 sweep between frequencies like all high quality frequency generators?

A: Yes. One of the great features of the GB-4000 is that it is capable of doing two kinds of sweep functions.

1) SWEEP: Allows you to run a specified frequency range of your choosing, one frequency at a time. The instrument sweeps from your beginning frequency to your ending frequency.

2) CONVERGENCE SWEEP: Allows you to run two frequencies at a time over a specified frequency range of your choosing. The instrument sweeps from your beginning frequency to the ending frequency and at the same time sweeps from the ending frequency to the beginning frequency. The result is that the two frequencies sweep towards each other, then pass each other, one going up and the other going down and each ending where the other frequency began.

Q19: Why does the GB-4000 have a channel sweep capability which varies the frequency or frequencies from 2 Hertz to 10000 Hertz?

A: The GB-4000 has the capability to sweep when running any of the 2000 programmable auto channels. The new channel sweep covers a variable range from 2 Hertz to 10,000 Hertz. If you are running a frequency of 2000 Hertz and decide that you want a to sweep 1000 Hertz then the sweep will start at 1500 Hertz and will end at 2500 Hertz. This sweep always covers the frequency range chosen with half the frequency range dropping below the targeted frequency or frequencies to half the range going above the targeted frequency or frequencies used. This type of sweep is desirable when you want variability in your frequency or frequencies you are running.

Q20: Why do you use a membrane type keypad instead of the contact style?

A: Durability is the main reason. Membrane keypad switches are the industry standard and have been for many years. Almost all electronic devices that have keypads use them. They are built to last for many years. They replaced the contact style because they have fewer problems. They will generally outlast the electronics. We have had this type of keypad on our instrument for over 8 years under heavy use with very few problems.

Q21: How long will the GB-4000 last?

A: The GB-4000 is built to last a long time and 99.9 % of the instruments sold over the last several years are still working. Some manufacturers claim that their instrument will last a lifetime. We cannot and will not make that kind of misleading claim. Any instrument that cannot be repaired, even after years of use, is update to the current model for only $800. No other company that we know of offers this kind of replacement in the industry.

Q22: Is the GB-4000 easy to use?

A: Yes. Programming the GB-4000 is easy. Running an un-programmed frequency is also easy to do. To run a programmed channel all that the user has to do is press the Auto channel button, then enter the auto channel number using the keypad, then press the Run button. The GB-4000 then will run all the frequencies in the channel. To run an individual frequency all you have to do is press enter then put in the frequency you wish to use and then press run. Anyone can do this three step process.

Q23: Why does the GB-4000 cost less than almost all the other instruments when it has far more features?

A: There are no middlemen to make it more expensive.

 


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