PSK Paging link

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Paging Modes: AFSK Paging Link - POCSAG - Glenayre Paging Link - PSK paging link - FLEX - ReFLEX - Golay Paging (GSC) - ERMES

PSK paging link
Purc signaling.png
Frequencies 470 MHz,150 MHz
Frequency Range 150 MHz - 470 MHz
Mode FM
Modulation PSK
Emission Designator
Bandwidth 12.5 kHz
Location United States
Short Description Also known as PSK paging, is a variant of AFSK paging link that allows sub-PSK modes to be modulated from the main pulse train and using notch filters to produce a dynamic sound to it.
I/Q Raw Recording
Audio Sample

Only one signal exists for this type of modulation: 454.475 MHzMegaHertz (MHz) 10^6 Hz In Chicago, IL.


For these signals they are chosen to use v.27ter modulation-esque sounds but with some differences. For the sample we listed, the Chicago's 454.475 transmitter is using some other maths behind their own methods. The following below describes a simpler method to form the waveforms:

For a good sounding example *idle* tone:

1. you will need a square wave at 37.5 HzHertz (Hz), unit of frequency, defined as one cycle per second (1 Hz). modulated with an FMFrequency Modulation center carrier of 1800 hz, with the deviation set at 500 hz, and 4000 hz bandwidth. 2. Modulate the same waveform *again* with a *600* hz sine, at least two to three times. This forms semi-harmonics that will sound distorted. 3.

FOR PREAMBLES: YOU CAN USE YOUR 1200 B/S PREAMBLES AS LONG AS THEY MATCH IT WITH 2400b/s. For 512 and 1200 bits per second waveforms: These modes are usually achieved by using a 1800 hz carrier wave (standard wise, on the audio spectrum). Or by offseting the carrier a bit by using a LSBLower Side Band Modulation or USBUpper Side Band Modulation (Radio, referring to reception and modulation mode)Universal Serial Bus (Computer, referring to USB Ports and cables) modulator.

To Achieve the dynamic PSKPhase-Shift Keying shifts (or in modem terms, a v.27ter modulation-sound), @2400 bits/sec, at least two notch filters are usually required: The specs for both of these notches exist 600hz for the first notch and 2700 hz for the second notch. Anything less or more will screw up the v.27ter sound achieved. You will also probably need a 4200 hz notch as well.

example samples[edit]

When processed, it will achieve similar characteristics...: I have provided several audio clips with variants of offsets (1600-1800 hz).

a standard "1800" hz set of preambles and data. I did the same idle tone for the examples you would do:

example IQQuadrature signals form the basis of complex RF signal modulation and demodulation, both in hardware and in software, as well as in complex signal analysis.:[edit]


Live streams[edit]

Spot is reserved for another time...

Additional Samples:[edit]