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#
# Copyright 2005 Free Software Foundation, Inc.
#
# This file is part of GNU Radio
#
# GNU Radio is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation; either version 3, or (at your option)
# any later version.
#
# GNU Radio is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with GNU Radio; see the file COPYING. If not, write to
# the Free Software Foundation, Inc., 51 Franklin Street,
# Boston, MA 02110-1301, USA.
#
__all__ = ['tv_rx']
import math
from usrpm import usrp_dbid
import db_base
import db_instantiator
def int_seq_to_str(seq):
"""convert a sequence of integers into a string"""
return ''.join (map (chr, seq))
def str_to_int_seq(str):
"""convert a string to a list of integers"""
return map (ord, str)
def control_byte_4():
C = 0 # Charge Pump Current, no info on how to choose
R = 4 # 125 kHz fref
ATP = 7 # Disable internal AGC
return 0x80 | C<<5 | R
def control_byte_5(freq,agcmode = 1):
if(agcmode):
if freq < 150e6:
return 0x3B
elif freq < 420e6:
return 0x7E
else:
return 0xB7
else:
if freq < 150e6:
return 0x39
elif freq < 420e6:
return 0x7C
else:
return 0xB5
def control_byte_6():
ATC = 0 # AGC time constant = 100ms, 1 = 3S
IFE = 1 # IF AGC amplifier enable
AT = 0 # AGC control, ???
return ATC << 5 | IFE << 4 | AT
def control_byte_7():
SAS = 1 # SAW Digital mode
AGD = 1 # AGC disable
ADS = 0 # AGC detector into ADC converter
T = 0 # Test mode, undocumented
return SAS << 7 | AGD << 5 | ADS << 4 | T
class db_dtt768(db_base.db_base):
def __init__(self, usrp, which):
"""
Control custom DTT76803-based daughterboard.
@param usrp: instance of usrp.source_c
@param which: which side: 0 or 1 corresponding to RX_A or RX_B respectively
@type which: int
"""
# sets _u and _which
db_base.db_base.__init__(self, usrp, which)
self._i2c_addr = (0x60, 0x62)[which]
self._IF = 44e6
self.f_ref = 125e3
self._inverted = False
g = self.gain_range() # initialize gain
self.set_gain(float(g[0]+g[1]) / 2)
self.bypass_adc_buffers(False)
# Gain setting
def _set_rfagc(self,gain):
assert gain <= 60 and gain >= 0
# FIXME this has a 0.5V step between gain = 60 and gain = 59.
# Why are there two cases instead of a single linear case?
if gain == 60:
voltage = 4
else:
voltage = gain/60.0 * 2.25 + 1.25
dacword = int(4096*voltage/1.22/3.3) # 1.22 = opamp gain
assert dacword>=0 and dacword<4096
self._u.write_aux_dac(self._which, 1, dacword)
def _set_ifagc(self,gain):
assert gain <= 35 and gain >= 0
voltage = gain/35.0 * 2.1 + 1.4
dacword = int(4096*voltage/1.22/3.3) # 1.22 = opamp gain
assert dacword>=0 and dacword<4096
self._u.write_aux_dac(self._which, 0, dacword)
def _set_pga(self,pga_gain):
assert pga_gain >=0 and pga_gain <=20
if(self._which == 0):
self._u.set_pga (0, pga_gain)
else:
self._u.set_pga (2, pga_gain)
def gain_range(self):
return (0, 115, 1)
def set_gain(self,gain):
assert gain>=0 and gain<=115
if gain>60:
rfgain = 60
gain = gain - 60
else:
rfgain = gain
gain = 0
if gain > 35:
ifgain = 35
gain = gain - 35
else:
ifgain = gain
gain = 0
pgagain = gain
self._set_rfagc(rfgain)
self._set_ifagc(ifgain)
self._set_pga(pgagain)
def freq_range(self):
return (44e6, 900e6, 10e3)
def set_freq(self, target_freq):
"""
@returns (ok, actual_baseband_freq) where:
ok is True or False and indicates success or failure,
actual_baseband_freq is the RF frequency that corresponds to DC in the IF.
"""
r = self.freq_range()
if target_freq < r[0] or target_freq > r[1]:
return (False, 0)
target_lo_freq = target_freq + self._IF; # High side mixing
divisor = int(0.5+(target_lo_freq / self.f_ref))
actual_lo_freq = self.f_ref*divisor
if (divisor & ~0x7fff) != 0: # must be 15-bits or less
return (False, 0)
# build i2c command string
buf = [0] * 6
buf[0] = (divisor >> 8) & 0xff # DB1
buf[1] = divisor & 0xff # DB2
buf[2] = control_byte_4()
buf[3] = control_byte_5(target_freq)
buf[4] = control_byte_6()
buf[5] = control_byte_7()
ok = self._u.write_i2c(self._i2c_addr, int_seq_to_str (buf))
self.freq = actual_lo_freq - self._IF
return (ok, actual_lo_freq)
def is_quadrature(self):
"""
Return True if this board requires both I & Q analog channels.
This bit of info is useful when setting up the USRP Rx mux register.
"""
return False
def spectrum_inverted(self):
"""
The 43.75 MHz version is inverted
"""
return self._inverted
# hook this daughterboard class into the auto-instantiation framework
# With DTT76803
db_instantiator.add(usrp_dbid.DTT768,
lambda usrp, which : (db_dtt768(usrp, which),))
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