Skip to main content

FM Ratio Detector: FM ratio discriminator working and principle

The ratio FM detector, discriminator or demodulator was widely used for FM demodulation for radio receivers that typically used discrete components. Now with radios using integrated circuits other forms of FM demodulator are more applicable.
When used, the FM ratio detector was able to provide good levels of performance with limited number of components.
The FM ratio detector may also be called an FM ratio demodulator or even an FM ratio discriminator.

The two main types of FM detector or demodulator that were used in circuits using discrete components were the ratio detector and the Foster-Seeley FM detector.
Both types were widely used, but the FM ratio detector was the more common because it offered a better level of amplitude modulation rejection of amplitude modulation. This enabled the circuit to provide a greater level of noise immunity as most noise is amplitude noise. It also enabled the FM detector to operate more effectively even with with lower levels of limiting in the preceding IF stages of the receiver.

Ratio detector advantages & disadvantages

As with any circuit there are a number of advantages and disadvantages to be considered when choosing between several options.
Advantages of the ratio FM detector
  • Simple to construct using discrete components.
  • Offers good level of performance and reasonable linearity.
  • Provides a good level of immunity to amplitude noise .
  • Ratio detector has wider bandwidth than Foster Seeley discriminator.
  • Disadvantages of the FM ratio detector
  • High cost of transformer.
  • Typically lends itself to use in only circuits using discrete components and not integrated within an IC.
  • Only 50% output of the Foster-Seeley discriminatorHigher distortion level than Foster-Seeley discriminator.
As a result of its advantages and disadvantages the FM ratio detector is not widely used these days as most radios - even low cost ones use integrated circuits. The ratio detector performs well, but the high cost of the transformer as well as the fact that there are other circuits and approaches that better lend themselves to use in integrated circuits means that this circuit is not widely used today.












Comments

Post a Comment

Popular posts from this blog

Design Engineer at Infineon Bangalore

  Hello Dear Readers, Currently at Infineon Bangalore vacancy for the Design Engineer role. Design analog and mixed-signal modules in CMOS and Smart PowerTechnologies, with a particular focus on achieving high-efficiency power conversion for applications using GaN devices; In your new role you will: Design analog and mixed-signal modules  in CMOS and Smart PowerTechnologies, with a particular focus on achieving high-efficiency power conversion for applications using GaN devices; Design and verify pre-silicon analog/mixed-signal integrated circuit blocks, including incorporating features for testing and quality assurance, and providing support for top-level integration; Assist in defining the requirements  for analog and mixed-signal blocks,aligning them with IP Module architecture, and ensuring compliance with requirements through documentation; Estimate effort and planning design work packages to meet project milestones; Provide essential support to physical design ...
1 comment
Read more

Engineer II - Analog Design Engineering at Microchip

Hello Dear Readers,   Currently at Microchip  vacancy for Engineer II - Analog Design Engineering role. Job Description: The Mixed Signal Development Group is responsible for delivering analog, digital and mixed-signal IP to divisions within Microchip. We work with leading edge CMOS processes to produce analog integrated circuits for wireline applications. From 112Gb/s+ SERDES to high-speed FEC engines, we enable technology that allows Microchip’s products to interface to the outside world.  Job Descriptions: As a member of the Mixed-Signal Development Group, the candidate will be supervised by a team leader/manager, and be engaged in the design of SERDES/DSP blocks, and other high-speed Digital Signal Processing blocks. This will involve taking a design from initial concept to production form. Throughout you will be mentored and coached by experienced engineers and be exposed to Microchip's Best-In-Class engineering practices. Job Responsibilities: Ramping up o...
2 comments
Read more

Analog Design Engineer II at onsemi

Hello Dear Readers,   Currently at onsemi  vacancy for  Analog Design  Engineer II role. JOB DESCRIPTION: An analog design engineer is expected to quickly take an analog design block through all phases of the development process, including design, simulation, and supervision of the layout/verification processes and evaluation/debug of silicon samples. A Senior Analog IC Design Engineer will be responsible for individual block designs using CMOS process. That person will work with the latest Cadence analogue design tools (Virtuoso Composer, Verilog) Spectre and appropriate PC-based tools (MATLAB). The nature of the circuits is Mixed Signal involving blocks such as switched capacitor amplifiers, data converters, charge pumps, references, voltage buffers, IO circuits and digital building blocks. QUALIFICATIONS: Analog engineer is expected to have PhD (no experience) or master’s degree in field of Electrical Engineering/VLSI/Electronics with 0-2 years of experience and w...
1 comment
Read more