Heterodyne vs superheterodyne

Heterodyne Regenerative and Super Regenerative. I want to try to answer that question here because I must have left something ambiguous in that article. By combining the two words we see that it literately means a different power.

A heterodyne is a signal which is produced by mixing two or more signals in a non linear device or to say it another way heterodyning is the process of mixing two or more signal frequencies to produce a different frequency signal.

superheterodyne

When two frequencies are mixed they actually produce two new frequencies. In that case, considering KHz is a very common IF frequency, the KHz signal would probably be the one desired and the The technique of heterodyning was developed by a Canadian inventor and engineer named Reginald Fessenden. After the process of heterodyning was developed and understood the superheterodyne receiver could be developed.

Prior to the superheterodyne receiver and after amplification was possible receivers had a series of RF amplifiers ahead of the detector. Each of these amplifiers had to be retuned when the receiver frequency was changed.

The superheterodyne receiver eliminated the need to have a series of RF amplifiers that had to be tuned separately. Normally there is one RF amplifier ahead of the mixer though there can be more and sometimes the mixer is the first stage.

The input to the mixer is tuned and the frequency of the local oscillator which produces the signal to be mixed with the incoming frequency can be variable in some cases the local oscillator is crystal controlled so the output frequency always remains the same. Each RF amplifier, which is actually called Intermediate Frequency IF amplifier, can be tuned to the same frequency no matter what the input frequency is.

Using an IF frequency allows the construction of more selective circuits. Fixed frequency filters can be easily added to the IF giving a far greater selectivity then possible with simple LC circuits.

Ease of tuning, improved gain, and increased selectivity are three advantages of the Superhetrodyne receiver. Another advantage was provided by the fixed If frequency being fed into the detector is it allows the signal of the IF to be mixed with the signal produced by the beat frequency oscillator BFO which makes receiving CW and SSB much easier the BFO heterodynes the IF frequency down to audio frequencies.

Regeneration is a process whereby some of the output signal of an amplifier is sent back, in phase, to the input.

When the output of an amplifier is sent back to the input it is called feedback. When a sufficient amount of the output signal is sent back to the input in phase the amplifier will sustain its own signal producing process called oscillation. Feedback can be regenerative positive feedback or in phase feedback and degenerative negative feedback or out of phase feedback.

As the article I mentioned above describes, the regenerative receiver used a small amount of positive feedback to improve the receivers amplification and its selectivity so one tube acting as the RF amplifier and detector worked very efficiently.

When the feedback was increased to the point where it started to oscillate a signal was being produced which would mix with the incoming signal to produce a tone so a CW signal could be read. A super-regenerative receiver is a regenerative receiver which uses a quenching frequency to prevent oscillation.

So I guess the answer to the question I was asked is heterodyne and regeneration are two different processes and regenerative and super-regenerative differ in that the latter uses a quenching frequency. The problem is that I was asked what the difference was between a Heterodyne Regenerative and a Super Regenerative receiver is and the only answer I have there is I have never heard of a Heterodyne Regenerative nor could I find any information when I researched this kind of receiver. This post is so help to me!

Thanks for share.I noticed a couple of my digital portables have Superheterdyne while the others have Heterodyne.

heterodyne vs superheterodyne

Is there a difference, or is this just radio marketing jargon? Top Superheterodyne vs. During my lifetime it's been superhet. Righty then. Tanks a wat! Superheterodyne is a circuit invented by Major Armstrong, I believe, that at the time s or 30s was better than regenerative or whatever else they had. For a while, it was patented by RCA and you needed a license to manufacture superheterodynes. This is the source of the nomenclature. Now it's more a generic term. I would guess that unless a radio uses DSP it's pretty much all the same circuits, due to large-scale integration.

Like the other gentleman said, what you're really looking for is multiple conversion on HF, though solid state mixers are so easy to design that it's almost a given.

Radios that employ the principle of heterodyning i. I think that the name goes all the way back to the Edwin Armstrong days. If modern receivers are starting to be called "heterodyne", either something got lost in the translation, or perhaps today's manufacturers consider the "super" part of the word archaic.

Very interesting. Thanks for your help. Got any mods?

superheterodyne receiver

This made the regenerative set go into and out of oscillation at a fairly high frequency, which kept it from going totally into oscillation, thereby improving the sensitivity over a standard regenerative receiver. This is a very good point. I had not considered the presence of the superregenerative at the same time The word at that time meaning "above audio frequency" rather than todays meaning of "faster than the speed of sound". Major Armstrong invented the super-regenerative receiver before he invented the superheterodyne.

I read somewhere a long time ago I wish I could remember where because I like to post references that he used the term super-regen because the regeneration was turned on and off at a supersonic rate today we would say ultrasonic. This was in the days before the speed of sound was broken and it was common to refer to frequencies that are above the range of human hearing as supersonic.

As has been mentioned, heterodyne refers to the mixing of two frequencies. In early superhets single conversion the IF frequency was above the range of human hearing 50kHz to kHz so Armstrong called it a superheterodyne. I wish I could remember the reference, but it said that the super refered to supersonic.

You're probably right. I had not considered the "supersonic" angle here. I like this explanation even more I looked the words up in my dictionary. Webster's agrees with you Dave. They say the "super" is from "supersonic". If the IF is not supersonic the mixing process would interfere with the audio signal. PLL vs. Heterodyne tuning?The understanding of both architectures is a must in order to design the right solution for 4G base transceiver stations.

With 4G wireless standards such as WiMAX and LTE poised for deployment, many cellular network operators are looking for more efficient use of wireless spectrum and cellular base transceiver station BTS sites to support cost-effective network rollouts.

With these needs, demand is increasing for remote radio heads to support multiantenna transceiver architectures such as diversity, MIMO, and smart antennas. In many cases, as many as four receive and four transmit channels 4x4 in one radio are required. Such multiantenna receivers provide the ability to offer wide cellular coverage areas in diverse environments, while still maintaining necessary performance levels to receive and transmit the large bandwidths required for 4G and multicarrier 2G and 3G standards.

But because each channel requires its own RF-to-DSP signal chain, building a size- power- and cost-efficient radio head to support a 4x4 system can be a great challenge. Each radio head antenna needs its own receiver low-noise amplifier LNA. Digital baseband processor needs depend heavily on the standard, bandwidth, and receiver count. However, the architecture by which the received RF signal is converted to digital baseband is not as constrained.

Because of this flexibility, the receiver portion of a 4G, 4x4 base station can be configured along two main architectural paths: an IF sampling receiver with heterodyne mixing stages down-converting the carrier frequency to the IF sampled by the ADC; and a direct down-conversion receiver in which the carrier frequency is converted through quadrature demodulation into two baseband signals for digital conversion.

The heterodyne IF sampling receive architecture see Fig. A series of passive and active components including transformers, mixers, amplifiers, attenuators, and active, passive, and SAW filters is needed to down-convert the carrier RF to either a low or high IF for sampling while maintaining signal integrity.

Because each of the main blocks comprises discrete or lightly integrated components, the heterodyne architecture is very flexible and allows for a basic design to be easily modified for accommodating different wireless standards and carrier frequencies. But due to the large number of discrete components required, heterodyne systems use large amounts of board area and can become cost challenging when not using commonly available components. These drawbacks are multiplied when designing multiple antennae systems.

In the heterodyne architecture much of the analog performance burden rests on the ADC and gain block driving it, typically an active filter or transformer with a passive anti-aliasing filter. Additionally, the ADC must operate with a sampling frequency more than twice that of the sampling bandwidth so that the antialiasing filter skirts can drop from passband to stopband without crossing into adjacent Nyquist zones.

Many systems, though, use a sampling rate of Lower IFs such as those centered in the middle of the first or second Nyquist zone, IFs centered in the third At MHz IF, it has typical At MHz, the performance drops to But this induces a direct cost increase as bit ADCs are more costly than bit ones.

Red Wave Radio

However, some of this cost increase can be mitigated as the higher IF can improve filter performance, allowing the use of lower-sampling-speed, lower-cost ADCs.

In the direct down-conversion receiver see Fig.To save this word, you'll need to log in. See more words from the same year Dictionary Entries near superheterodyne superhero superheroine superhet superheterodyne superhigh frequency superhighway superhistorical. Accessed 12 Apr.

How Do Superheterodyne Radios Work?

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Take the quiz Add Diction Build a chain of words by adding one letter at a time. Play the game.It is useful to have an understanding of the different signal blocks, their functions, and the overall signal flow, not only for the RF circuit design, but also from an operational viewpoint. It is possible to get the best performance by understanding its internal RF design and function.

There are several different circuit blocks that make up the overall receiver, each one has its own function. Whilst the superheterodyne receiver block diagram below is the most basic format, it serves to illustrate the operation. More complicated receivers with more complicated block diagrams are often seen as these radios are able to offer better performance and more facilities. There are some key circuit blocks within the RF design of the basic superheterodyne receiver.

Although more complicated receivers can be made, the basic RF circuit design is widely used — further blocks can add improved performance or additional functionality and their operation within the whole receiver is normally easy to determine once the basic block diagram is understood.

It also provides some amplification. There are many different approaches used within the RF circuit design for this block dependent its application. The RF circuit design presents some challenges. Low cost broadcast radios may have an amplifying mixer circuit that gives some RF amplification.

HF radios may not want too much RF gain because some of the very strong signals received could overload later stages. The RF design may incorporate some amplification as well as RF attenuation to overcome this issue.

Radios for VHF and above will tend to use more gain to have a sufficiently low noise figure to receive the signal. If noise performance for the receiver is important, then this stage will be designed for optimum noise performance.

This RF amplifier circuit block will also increase the signal level so that the noise introduced by later stages is at a lower level in comparison to the wanted signal. Early receivers used free running local oscillators. There was a considerable degree of RF circuit design expertise used with these oscillators in high performance superhet radios to ensure the lowest possible drift. High Q coils, low drift circuit configurations, heat management because heat causes driftetc.

Today most receivers use one or more of a variety of forms frequency synthesizers.Heterodyning is a signal processing technique invented by Canadian inventor-engineer Reginald Fessenden that creates new frequencies by combining or mixing two frequencies. Typically only one of the new frequencies is desired, and the other signal is filtered out of the output of the mixer.

Heterodyne frequencies are related to the phenomenon of " beats " in acoustics. A major application of the heterodyne process is in the superheterodyne radio receiver circuit, which is used in virtually all modern radio receivers. InReginald Fessenden demonstrated a direct-conversion heterodyne receiver or beat receiver as a method of making continuous wave radiotelegraphy signals audible. A stable yet inexpensive local oscillator was not available until Lee de Forest invented the triode vacuum tube oscillator.

heterodyne vs superheterodyne

In radio telegraphy, the characters of text messages are translated into the short duration dots and long duration dashes of Morse code that are broadcast as radio signals. Radio telegraphy was much like ordinary telegraphy. One of the problems was building high power transmitters with the technology of the day. Early transmitters were spark gap transmitters. This ringing would quickly decay, so the output of the transmitter would be a succession of damped waves. When these damped waves were received by a simple detector, the operator would hear an audible buzzing sound that could be transcribed back into alpha-numeric characters.

With the development of the arc converter radio transmitter incontinuous wave CW modulation began to be used for radiotelegraphy. CW Morse code signals are not amplitude modulated, but rather consist of bursts of sinusoidal carrier frequency. When CW signals are received by an AM receiver, the operator does not hear a sound.

The direct-conversion heterodyne detector was invented to make continuous wave radio-frequency signals audible. The "heterodyne" or "beat" receiver has a local oscillator that produces a radio signal adjusted to be close in frequency to the incoming signal being received.

When the two signals are mixed, a "beat" frequency equal to the difference between the two frequencies is created. By adjusting the local oscillator frequency correctly, the beat frequency is in the audio range, and can be heard as a tone in the receiver's earphones whenever the transmitter signal is present.

Thus the Morse code "dots" and "dashes" are audible as beeping sounds. This technique is still used in radio telegraphy, the local oscillator now being called the beat frequency oscillator or BFO.

Fessenden coined the word heterodyne from the Greek roots hetero- "different", and dyn- "power" cf. An important and widely used application of the heterodyne technique is in the superheterodyne receiver superhetwhich was invented by U. In the typical superhet, the incoming radio frequency signal from the antenna is mixed heterodyned with a signal from a local oscillator LO to produce a lower fixed frequency signal called the intermediate frequency IF signal.

The IF signal is amplified and filtered and then applied to a detector that extracts the audio signal; the audio is ultimately sent to the receiver's loudspeaker.

The superheterodyne receiver has several advantages over previous receiver designs. One advantage is easier tuning; only the RF filter and the LO are tuned by the operator; the fixed-frequency IF is tuned "aligned" at the factory and is not adjusted.

heterodyne vs superheterodyne

In older designs such as the tuned radio frequency receiver TRFall of the receiver stages had to be simultaneously tuned. In addition, since the IF filters are fixed-tuned, the receiver's selectivity is the same across the receiver's entire frequency band.A superheterodyne receiveroften shortened to superhetis a type of radio receiver that uses frequency mixing to convert a received signal to a fixed intermediate frequency IF which can be more conveniently processed than the original carrier frequency.

The word heterodyne is derived from the Greek roots hetero- "different", and -dyne "power". In radio applications the term derives from the "heterodyne detector" pioneered by Canadian inventor Reginald Fessenden indescribing his proposed method of producing an audible signal from the Morse code transmissions of the new continuous wave transmitters. With the older spark gap transmitters then in use, the Morse code signal consisted of short bursts of a carrier wave.

Since these bursts were derived from the output of an alternator, they modulated the carrier at a frequency within the audio range and thus could be heard as a chirp or a buzz in the receiver's headphones. However, the signal from a continuous wave transmitter is at a single frequency well above the audio range, and Morse Code from one of these would be heard only as a series of clicks or thumps.

For this he coined the term "heterodyne," meaning "generated by a difference" in frequency. Schottky also filed a patent in Armstrong invented his receiver as a means of overcoming the deficiencies of early vacuum tube triodes used as high-frequency amplifiers in radio direction finding equipment. Unlike simple radio communication, which needs only to make transmitted signals audible, direction-finders measure the received signal strength, which necessitates linear amplification of the actual carrier wave.

In a triode radio-frequency RF amplifier, if both the plate anode and grid are connected to resonant circuits tuned to the same frequency, stray capacitive coupling between the grid and the plate will cause the amplifier to go into oscillation if the stage gain is much more than unity. In early designs, dozens in some cases over low-gain triode stages had to be connected in cascade to make workable equipment, which drew enormous amounts of power in operation and required a team of maintenance engineers.

The strategic value was so high, however, that the British Admiralty felt the high cost was justified. Armstrong realized that if radio direction-finding RDF receivers could be operated at a higher frequency, this would allow better detection of enemy shipping. It had been noticed that when a regenerative receiver went into oscillation, other nearby receivers would suddenly start picking up stations on frequencies different from the stations' transmission frequency.

Armstrong and others eventually deduced that this was caused by a "supersonic heterodyne" between the station's carrier frequency and the regenerative receiver's oscillation frequency. Armstrong realized that this was a potential solution to the "short wave" amplification problem, since the beat frequency still retained its original modulation, but on a lower carrier frequency.

He termed this the " intermediate frequency " often abbreviated to "IF". In DecemberMajor E. Armstrong gave publicity to an indirect method of obtaining short-wave amplification, called the super-heterodyne.

The idea is to reduce the incoming frequency, which may be, say 1, cycles metersto some suitable super-audible frequency that can be amplified efficiently, then passing this current through an intermediate frequency amplifier, and finally rectifying and carrying on to one or two stages of audio frequency amplification. Armstrong was able to put his ideas into practice, and the technique was soon adopted by the military.

However, it was less popular when commercial radio broadcasting began in the s, mostly due to the need for an extra tube for the oscillatorthe generally higher cost of the receiver, and the level of technical skill required to operate it.

For early domestic radios, tuned radio frequency receivers TRF were more popular because they were cheaper, easier for a non-technical owner to use, and less costly to operate. Armstrong eventually sold his superheterodyne patent to Westinghousewho in turn sold it to the Radio Corporation of America RCAthe latter monopolizing the market for superheterodyne receivers until This made them extremely susceptible to image frequency interference, but at the time, the main objective was sensitivity rather than selectivity.

Using this technique, a small number of triodes could be made to do the work that formerly required dozens of triodes. In the s, commercial IF filters looked very similar to s audio interstage coupling transformers, had very similar construction and were wired up in an almost identical manner, and so they were referred to as "IF transformers".

However, the name "IF transformer" was retained and is still used today. Modern receivers typically use a mixture of ceramic resonator or SAW surface-acoustic wave resonators as well as traditional tuned-inductor IF transformers.

By the s, improvements in vacuum tube technology rapidly eroded the TRF receiver's cost advantages, and the explosion in the number of broadcasting stations created a demand for cheaper, higher-performance receivers. The development of the tetrode vacuum tube containing a screen grid led to a multi-element tube in which the mixer and oscillator functions could be combined, first used in the so-called autodyne mixer.

This was rapidly followed by the introduction of tubes specifically designed for superheterodyne operation, most notably the pentagrid converter. By reducing the tube count, this further reduced the advantage of preceding receiver designs. By the mids, commercial production of TRF receivers was largely replaced by superheterodyne receivers. From this time, the superheterodyne design was used for virtually all commercial radio and TV receivers.

The diagram at right shows the block diagram of a typical single-conversion superheterodyne receiver.


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