How to create linear phase filters for filter bank?

I tried firpr2chfb function as follows

N = 19;
[h0,h1,g0,g1] = firpr2chfb(N,.45);
fvtool(h0, 1, h1, 1)

I have something like, and I don't think these are linear phase filters

Answer 1

[Mathieu NOE]

hello

the phase roll rate must be constant like in the example below

%% define filters
fs =  10000;
freq = linspace(100,(fs/2),500);
% 1 - LPF FIR / cutoff frequency 3 KHz
N = 64;
fc_lp = 1000;
B_lp = fir1(N,2*fc_lp/fs);
h_lp=freqz(B_lp,1,freq,fs);
m_lp=20*log10(abs(h_lp));

% 2 - BPF FIR / cutoff frequencies 2 and 5 KHz
N = 64;
fc_low = 1000;
fc_high = 3000;
B_bp = fir1(N,2*[fc_low fc_high]/fs);
h_bp=freqz(B_bp,1,freq,fs);
m_bp=20*log10(abs(h_bp));

% 3 - HPF  FIR /  cutoff frequency 4 KHz
N = 64;
fc_high = 3000;
B_hp = fir1(N,2*fc_high/fs,'high');
h_hp=freqz(B_hp,1,freq,fs);
m_hp=20*log10(abs(h_hp));


figure(1),
subplot(211),plot(freq,m_lp,freq,m_bp,freq,m_hp);
title('FIR Filters Response');
ylabel('Gain in dB');
legend('LPF','BPF','HPF');
subplot(212),plot(freq,180/pi*angle(h_lp),freq,180/pi*angle(h_bp),freq,180/pi*angle(h_hp));
ylabel('Phase(°)');
xlabel('Frequency (Hz)');
legend('LPF','BPF','HPF');

[soso maths]

Thank you @Mathieu NOE, this is for the synthesis part, what about the analysis part? How can we compute the group delay of the filter bank in terms of filter length N and number of channels M?

[Mathieu NOE]

hello

as far as I remember , linear-phase FIR filter overall group delay is (N-1)/2 where N is the length of the filter

I don't see where the channel number's has an impact on group delay