CHU Time Signal Decoder
Decodes the CHU shortwave time code from a 14670 kHz recording.
- Author Marc
- Category Ham Radio
- Blocks 14
- Connections 8
- File
ham/chu_time_signal.grc
Blocks used
| Block | Module | Used |
|---|---|---|
| Variable | GNU Radio | 4 |
| Binary Slicer | GNU Radio | 1 |
| CHU Decoder | gr-ham | 1 |
| Frequency Xlating FIR Filter | GNU Radio | 1 |
| GR World Recording | GNU Radio | 1 |
| IShort To Complex | GNU Radio | 1 |
| Note | GNU Radio | 1 |
| QT GUI Time Sink | GNU Radio | 1 |
| QT GUI Waterfall Sink | GNU Radio | 1 |
| Quadrature Demod | GNU Radio | 1 |
| Throttle | GNU Radio | 1 |
Notes in this flowgraph
- 300 baud AFSK on the Bell 103 tones; burst arrives 21 s in
Flowgraph source
ham/chu_time_signal.grc
options:
parameters:
author: Marc
copyright: ''
description: Decodes the CHU shortwave time code from a 14670 kHz recording.
generate_options: qt_gui
id: CHU_Time_Signal_Decoder
title: CHU Time Signal Decoder
states:
coordinate: [10, 10]
rotation: 0
state: enabled
blocks:
- name: channel_rate
id: variable
parameters:
comment: ''
value: '4800'
states:
coordinate: [600, 10]
rotation: 0
state: enabled
- name: mark_tone
id: variable
parameters:
comment: ''
value: '2225'
states:
coordinate: [790, 10]
rotation: 0
state: enabled
- name: samp_rate
id: variable
parameters:
comment: ''
value: '48000'
states:
coordinate: [960, 10]
rotation: 0
state: enabled
- name: space_tone
id: variable
parameters:
comment: ''
value: '2025'
states:
coordinate: [1130, 10]
rotation: 0
state: enabled
- name: chu_decoder
id: ham_chu_decode
parameters:
affinity: ''
alias: ''
comment: ''
states:
coordinate: [760, 370]
rotation: 0
state: enabled
- name: complex17
id: blocks_interleaved_short_to_complex
parameters:
affinity: ''
alias: ''
comment: ''
maxoutbuf: '0'
minoutbuf: '0'
scale_factor: '32767'
swap: 'False'
vector_input: 'False'
states:
coordinate: [370, 220]
rotation: 0
state: enabled
- name: discriminator
id: analog_quadrature_demod_cf
parameters:
affinity: ''
alias: ''
comment: ''
gain: channel_rate/(math.pi*(mark_tone - space_tone))
maxoutbuf: '0'
minoutbuf: '0'
states:
coordinate: [80, 370]
rotation: 0
state: enabled
- name: intro
id: note
parameters:
affinity: ''
alias: ''
comment: ''
note: 300 baud AFSK on the Bell 103 tones; burst arrives 21 s in
states:
coordinate: [1300, 10]
rotation: 0
state: enabled
- name: slicer
id: digital_binary_slicer_fb
parameters:
affinity: ''
alias: ''
comment: ''
maxoutbuf: '0'
minoutbuf: '0'
states:
coordinate: [450, 370]
rotation: 0
state: enabled
- name: source16
id: wasm_gr_world_recording
parameters:
affinity: ''
alias: ''
comment: ''
length: '0'
maxoutbuf: '0'
minoutbuf: '0'
offset: '0'
recording: ham_chu_14670kHz
repeat: 'True'
type: short
states:
coordinate: [10, 190]
rotation: 0
state: enabled
- name: symbols
id: qtgui_time_sink_x
parameters:
affinity: ''
alias: ''
alpha1: '1'
alpha2: '1'
autoscale: 'False'
axislabels: 'True'
color1: blue
color2: red
comment: ''
ctrlpanel: 'False'
grid: 'True'
label1: Discriminator
label2: Signal 2
legend: 'True'
marker1: '-1'
marker2: '0'
name: FSK discriminator
samp_rate: channel_rate
size: '4800'
stemplot: 'False'
style1: '1'
style2: '1'
tr_chan: '0'
tr_delay: '0'
tr_level: '0'
tr_mode: qtgui.TRIG_MODE_FREE
tr_slope: qtgui.TRIG_SLOPE_POS
tr_tag: ''
type: float
update_time: '0.1'
width1: '1'
width2: '1'
ylabel: Amplitude
ymax: '2'
ymin: '-2'
yunit: ''
states:
coordinate: [450, 470]
rotation: 0
state: enabled
- name: throttle
id: blocks_throttle2
parameters:
affinity: ''
alias: ''
comment: ''
ignoretag: 'True'
limit: auto
maximum: '0.1'
maxoutbuf: '0'
minoutbuf: '0'
samples_per_second: samp_rate*10
type: complex
vlen: '1'
states:
coordinate: [680, 200]
rotation: 0
state: enabled
- name: tone_channel
id: freq_xlating_fir_filter_xxx
parameters:
affinity: ''
alias: ''
center_freq: (mark_tone + space_tone)/2
comment: ''
decim: '10'
maxoutbuf: '0'
minoutbuf: '0'
samp_rate: samp_rate
taps: firdes.low_pass(1, samp_rate, 250, 500)
type: ccf
states:
coordinate: [1020, 210]
rotation: 0
state: enabled
- name: waterfall
id: qtgui_waterfall_sink_x
parameters:
affinity: ''
alias: ''
alpha1: '1'
axislabels: 'True'
color1: '0'
comment: ''
fc: 14670000 + (mark_tone + space_tone)/2
fftsize: '1024'
grid: 'False'
int_max: '10'
int_min: '-110'
label1: ''
legend: 'True'
maxoutbuf: '0'
minoutbuf: '0'
name: CHU tone channel
samp_rate: channel_rate
update_time: '0.1'
states:
coordinate: [80, 470]
rotation: 0
state: enabled
connections:
- [complex17, '0', throttle, '0']
- [discriminator, '0', slicer, '0']
- [discriminator, '0', symbols, '0']
- [slicer, '0', chu_decoder, '0']
- [source16, '0', complex17, '0']
- [throttle, '0', tone_channel, '0']
- [tone_channel, '0', discriminator, '0']
- [tone_channel, '0', waterfall, '0']
metadata:
file_format: 1
grc_version: 3.11.0.0